[Libvir] Patch to get rid of index(3) and rindex(3)

According to index(3): [index and rindex appeared in] 4.3BSD; marked as LEGACY in POSIX.1-2001. Rich. -- Emerging Technologies, Red Hat - http://et.redhat.com/~rjones/ Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SL4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 03798903