libxc: Fix out-of-memory error handling in xc_cpupool_getinfo()

Avoid freeing info then returning it to the caller.

This is XSA-88.

Coverity-ID: 1056192
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
(cherry picked from commit d883c179a7)

tools/libxc/xc_cpupool.c

@@ -104,6 +104,7 @@ xc_cpupoolinfo_t *xc_cpupool_getinfo(xc_interface *xch,
     info->cpumap = xc_cpumap_alloc(xch);
     if (!info->cpumap) {
         free(info);
+        info = NULL;
         goto out;
     }
     info->cpupool_id = sysctl.u.cpupool_op.cpupool_id;