fix(dracut-install): use stripped kernel module path as hash key

fix(dracut-install): use stripped kernel module path as hash key

in install_dependent_modules we use &path[kerneldirlen] as the key for inserting,
let's do the same for checking.

otherwise installing kernel module has circular dependency from a custom kernel
module directory will cause infinite recursion and segfault.

$ grep ipmi kbuilt/lib/modules/5.10.121/modules.dep
kernel/drivers/char/ipmi/ipmi_msghandler.ko:
kernel/drivers/char/ipmi/ipmi_devintf.ko: kernel/drivers/char/ipmi/ipmi_msghandler.ko

$ grep ipmi kbuilt/lib/modules/5.10.121/modules.softdep
softdep ipmi_msghandler post: ipmi_devintf

$ ./dracut-install -D /tmp --kerneldir ~/working/kernel/linux-5.10.121/kbuilt/lib/modules/5.10.121 -m ipmi-devintf
Segmentation fault (core dumped)

(gdb) b install_dependent_modules
Breakpoint 1 at 0x7db0: file src/install/dracut-install.c, line 1513.
(gdb) bt
#0  install_dependent_modules (modlist=0x0) at src/install/dracut-install.c:1513
#1  0x000055555555c027 in install_dependent_modules (modlist=modlist@entry=0x555555579e90) at src/install/dracut-install.c:1553
#2  0x000055555555bf1c in install_dependent_modules (modlist=0x5555555799d0) at src/install/dracut-install.c:1548
#3  0x000055555555c034 in install_dependent_modules (modlist=modlist@entry=0x55555557a3f0) at src/install/dracut-install.c:1554
#4  0x000055555555bf1c in install_dependent_modules (modlist=0x555555579d60) at src/install/dracut-install.c:1548
#5  0x000055555555c034 in install_dependent_modules (modlist=modlist@entry=0x55555557b170) at src/install/dracut-install.c:1554
#6  0x000055555555bf1c in install_dependent_modules (modlist=0x55555557a0f0) at src/install/dracut-install.c:1548
#7  0x000055555555c034 in install_dependent_modules (modlist=modlist@entry=0x555555575320) at src/install/dracut-install.c:1554
#8  0x000055555555bf1c in install_dependent_modules (modlist=0x55555557ab30) at src/install/dracut-install.c:1548
#9  0x000055555555c034 in install_dependent_modules (modlist=modlist@entry=0x55555557dd60) at src/install/dracut-install.c:1554
#10 0x000055555555bf1c in install_dependent_modules (modlist=0x55555557b640) at src/install/dracut-install.c:1548
#11 0x000055555555c034 in install_dependent_modules (modlist=modlist@entry=0x55555557e0f0) at src/install/dracut-install.c:1554
#12 0x000055555555bf1c in install_dependent_modules (modlist=0x55555557b9d0) at src/install/dracut-install.c:1548
#13 0x000055555555c034 in install_dependent_modules (modlist=modlist@entry=0x555555574340) at src/install/dracut-install.c:1554
#14 0x000055555555bf1c in install_dependent_modules (modlist=0x55555557cf70) at src/install/dracut-install.c:1548
#15 0x000055555555c034 in install_dependent_modules (modlist=modlist@entry=0x5555555768d0) at src/install/dracut-install.c:1554
#16 0x000055555555bf1c in install_dependent_modules (modlist=0x55555557d750) at src/install/dracut-install.c:1548
#17 0x000055555555c034 in install_dependent_modules (modlist=modlist@entry=0x55555557e700) at src/install/dracut-install.c:1554
#18 0x000055555555bf1c in install_dependent_modules (modlist=0x55555557de90) at src/install/dracut-install.c:1548
#19 0x000055555555c034 in install_dependent_modules (modlist=modlist@entry=0x555555581c90) at src/install/dracut-install.c:1554
#20 0x000055555555bf1c in install_dependent_modules (modlist=0x555555571e60) at src/install/dracut-install.c:1548
#21 0x000055555555c034 in install_dependent_modules (modlist=modlist@entry=0x55555556b620) at src/install/dracut-install.c:1554
#22 0x000055555555bf1c in install_dependent_modules (modlist=0x555555583000) at src/install/dracut-install.c:1548
#23 0x000055555555c034 in install_dependent_modules (modlist=modlist@entry=0x55555556b640) at src/install/dracut-install.c:1554
#24 0x000055555555bf1c in install_dependent_modules (modlist=0x555555571b40) at src/install/dracut-install.c:1548
#25 0x000055555555c034 in install_dependent_modules (modlist=modlist@entry=0x555555574100) at src/install/dracut-install.c:1554
#26 0x000055555555c4b0 in install_module (mod=mod@entry=0x555555573bc0) at src/install/dracut-install.c:1617
#27 0x000055555555c93d in install_modules (argc=argc@entry=1, argv=argv@entry=0x7fffffffd6e0) at src/install/dracut-install.c:1952
#28 0x000055555555862a in main (argc=<optimized out>, argv=0x7fffffffd6a8) at src/install/dracut-install.c:2090

Signed-off-by: runsisi <runsisi@hust.edu.cn>