tests: Fix memory leak in mymain

Commit 944a35d7 added @fakerootdir; however, there are multiple
paths out of mymain that didn't free the memory - so just use the
g_autofree to resolve the potential leak.

Found by Coverity
Signed-off-by: NJohn Ferlan <jferlan@redhat.com>
Reviewed-by: NDaniel P. Berrangé <berrange@redhat.com>

tests/qemuhotplugtest.c

@@ -595,7 +595,7 @@ mymain(void)
     int ret = 0;
     struct qemuHotplugTestData data = {0};
     struct testQemuHotplugCpuParams cpudata;
-    char *fakerootdir;
+    g_autofree char *fakerootdir = NULL;
 
     fakerootdir = g_strdup(FAKEROOTDIRTEMPLATE);
 
@@ -875,7 +875,6 @@ mymain(void)
 
     if (getenv("LIBVIRT_SKIP_CLEANUP") == NULL)
         virFileDeleteTree(fakerootdir);
-    VIR_FREE(fakerootdir);
 
     qemuTestDriverFree(&driver);
     virObjectUnref(data.vm);