virConfGetValue: Fixed NULL pointer check

This patch fixes a NULL pointer check that was causing SegFault on
some specific configurations. It also reverts commit 59d0c980
that was checking for this value in one place.

src/libvirt.c

@@ -1085,8 +1085,7 @@ virConnectOpenResolveURIAlias(virConfPtr conf,
 
     *uri = NULL;
 
-    if (conf &&
-        (value = virConfGetValue(conf, "uri_aliases")))
+    if ((value = virConfGetValue(conf, "uri_aliases")))
         ret = virConnectOpenFindURIAliasMatch(value, alias, uri);
     else
         ret = 0;

src/util/conf.c

 /**
  * conf.c: parser for a subset of the Python encoded Xen configuration files
  *
- * Copyright (C) 2006-2011 Red Hat, Inc.
+ * Copyright (C) 2006-2012 Red Hat, Inc.
  *
  * See COPYING.LIB for the License of this software
  *
@@ -836,6 +836,9 @@ virConfGetValue(virConfPtr conf, const char *setting)
 {
     virConfEntryPtr cur;
 
+    if (conf == NULL)
+        return NULL;
+
     cur = conf->entries;
     while (cur != NULL) {
         if ((cur->name != NULL) &&