Initialize random generator in lxc controller

Initialize random generator in lxc controller

The lxc contoller eventually makes use of virRandomBits(), which was
segfaulting since virRandomInitialize() is never invoked.

Program received signal SIGSEGV, Segmentation fault.
0x00007ffff554d560 in random_r () from /lib64/libc.so.6
(gdb) bt
0  0x00007ffff554d560 in random_r () from /lib64/libc.so.6
1  0x0000000000469eaa in virRandomBits (nbits=32) at util/virrandom.c:80
2  0x000000000045bf69 in virHashCreateFull (size=256,
    dataFree=0x4aa2a2 <hashDataFree>, keyCode=0x45bd40 <virHashStrCode>,
    keyEqual=0x45bdad <virHashStrEqual>, keyCopy=0x45bdfa <virHashStrCopy>,
    keyFree=0x45be37 <virHashStrFree>) at util/virhash.c:134
3  0x000000000045c069 in virHashCreate (size=0, dataFree=0x4aa2a2 <hashDataFree>)
    at util/virhash.c:164
4  0x00000000004aa562 in virNWFilterHashTableCreate (n=0)
    at conf/nwfilter_params.c:686
5  0x00000000004aa95b in virNWFilterParseParamAttributes (cur=0x711d30)
    at conf/nwfilter_params.c:793
6  0x0000000000481a7f in virDomainNetDefParseXML (caps=0x702c90, node=0x7116b0,
    ctxt=0x7101b0, bootMap=0x0, flags=0) at conf/domain_conf.c:4589
7  0x000000000048cc36 in virDomainDefParseXML (caps=0x702c90, xml=0x710040,
    root=0x7103b0, ctxt=0x7101b0, expectedVirtTypes=16, flags=0)
    at conf/domain_conf.c:8658
8  0x000000000048f011 in virDomainDefParseNode (caps=0x702c90, xml=0x710040,
    root=0x7103b0, expectedVirtTypes=16, flags=0) at conf/domain_conf.c:9360
9  0x000000000048ee30 in virDomainDefParse (xmlStr=0x0,
    filename=0x702ae0 "/var/run/libvirt/lxc/x.xml", caps=0x702c90,
    expectedVirtTypes=16, flags=0) at conf/domain_conf.c:9310
10 0x000000000048ef00 in virDomainDefParseFile (caps=0x702c90,
    filename=0x702ae0 "/var/run/libvirt/lxc/x.xml", expectedVirtTypes=16, flags=0)
    at conf/domain_conf.c:9332
11 0x0000000000425053 in main (argc=5, argv=0x7fffffffe2b8)
    at lxc/lxc_controller.c:1773
(cherry picked from commit 57349ffc10290eed2cb25ca7cfb4b34ab5003156)