conf: convert VIR_FREE to g_free in other functions that free their arg

conf: convert VIR_FREE to g_free in other functions that free their arg

Previous patches have converted VIR_FREE to g_free in functions with
names ending in Free() and Dispose(), but there are a few similar
functions with names that don't fit that pattern, but server the same
purpose (and thus can survive the same conversion). in particular
*Free*(), and *Unref().

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