conf: replace VIR_FREE() with g_free() in vir*Free() functions

conf: replace VIR_FREE() with g_free() in vir*Free() functions

This patch takes on one set of examples of unnecessary use of
VIR_FREE() when g_free() is adequate - it modifies only vir*Free()
functions within the conf directory that take a single pointer and
free the object pointed to by that argument before returning. The
modification is to replace VIR_FREE() with g_free() for the object
itself *and* for all subordinate chunks of memory pointed to by that
object.

(NB: there are other functions that VIR_FREE subordinate memory of
objects that end up being freed before return (also sometimes with
VIR_FREE); I am purposefully ignoring those to reduce scope and focus
on a sub class where the pointlessness is obvious.)

Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>