p2v: Move libutils before libxml2 in the list of libraries (RHBZ#1102447).

The error is:

../src/.libs/libutils.a(
libutils_la-cleanup.o): In function `guestfs___cleanup_xmlBufferFree':
cleanup.c:(.text+0x79): undefined reference to `xmlBufferFree'
../src/.libs/libutils.a(libutils_la-cleanup.o): In function
`guestfs___cleanup_xmlFreeDoc':
cleanup.c:(.text+0x99): undefined reference to `xmlFreeDoc'
[etc.]

Thanks: Arnaud Gaboury