apache2: Properly re-execute Apache on restart

apache2: Properly re-execute Apache on restart

Previously, we sent Apache a signal to relaunch itself which caused
Apache to kill all child processes, and re-execute them.

However, when updating glibc, any newly compiled modules could not be
loaded as Apache was running with the previous version of glibc until
the next reboot.

This change will now properly stop Apache and restart it which solves
this problem.

Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>