base-call: Fix in-call URC regex to match handler logic

The handler assumes the regex sub-expressions each have the same index
so they need to be within the same set of parentheses rather than each
individually parenthesised.  Without this fix, call state changes are
missed.

src/mm-base-call.c

@@ -99,7 +99,7 @@ common_setup_cleanup_unsolicited_events (MMBaseCall  *self,
     gint            i;
 
     if (G_UNLIKELY (!self->priv->in_call_events))
-        self->priv->in_call_events = g_regex_new ("\\r\\n(NO CARRIER)|(BUSY)|(NO ANSWER)|(NO DIALTONE)\\r\\n$",
+        self->priv->in_call_events = g_regex_new ("\\r\\n(NO CARRIER|BUSY|NO ANSWER|NO DIALTONE)\\r\\n$",
                                                   G_REGEX_RAW | G_REGEX_OPTIMIZE, 0, NULL);
 
     g_object_get (self,