Markus Armbruster <armbru@redhat.com> sent fixes for va_list vararg
issues in v9fs_string_alloc_printf(). It turns out the function
duplicates g_vasprintf() and can therefore be eliminated entirely.
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>