Fix UUID random generator to use /dev/random

Only use pseudo-random generator for uuid if using /dev/random fails.
* src/util/uuid.c: The original code. would only print the warning
  message if using /dev/random failed, but would still go ahead and call
  virUUIDGeneratePseudoRandomBytes in all cases anyway.

src/util/uuid.c

@@ -104,9 +104,10 @@ virUUIDGenerate(unsigned char *uuid)
         VIR_WARN(_("Falling back to pseudorandom UUID,"
                    " failed to generate random bytes: %s"),
                  virStrerror(err, ebuf, sizeof ebuf));
+        err = virUUIDGeneratePseudoRandomBytes(uuid, VIR_UUID_BUFLEN);
     }
 
-    return virUUIDGeneratePseudoRandomBytes(uuid, VIR_UUID_BUFLEN);
+    return(err);
 }
 
 /* Convert C from hexadecimal character to integer.  */