Just playing around and I created /etc/chkconfig.d/libvirtd with:

  # chkconfig: 345 98 02

and ran "chkconfig libvirtd resetpriorities" and got:

Program received signal SIGSEGV, Segmentation fault.
0x0019ce1a in strcmp () from /lib/libc.so.6
Missing separate debuginfos, use: debuginfo-install glibc-2.9-3.i686 popt-1.13-4.fc10.i386
(gdb) bt
#0  0x0019ce1a in strcmp () from /lib/libc.so.6
#1  0x080493ed in frobOneDependencies (s=0x80560ec, servs=<value optimized out>, numservs=74, target=0) at chkconfig.c:136
#2  0x080498e8 in frobDependencies (s=0xbffff4b0) at chkconfig.c:224
#3  0x0804a50f in setService (name=0xbffff906 "libvirtd", where=60, state=-2) at chkconfig.c:534
#4  0x0804affa in main (argc=3, argv=0xbffff7c4) at chkconfig.c:699

If I add another newline to the file, it doesn't segfault anymore.