Don't throw a spurious error when using DBdeltree

The function call ast_db_deltree returns the number of row deleted, or a
negative number if it failed. DBdeltree was treating any non-zero return
as an error, causing a spurious verbose error message to be displayed.

This patch handles the return code of ast_db_deltree correctly.

(closes issue ASTERISK-21070)
Reported by: ianc
patches:
  dbdeltree.diff uploaded by ianc (License #5955)
........

Merged revisions 381364 from http://svn.asterisk.org/svn/asterisk/branches/1.8
........

Merged revisions 381365 from http://svn.asterisk.org/svn/asterisk/branches/11


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@381366 65c4cc65-6c06-0410-ace0-fbb531ad65f3

apps/app_db.c

@@ -106,13 +106,15 @@ static int deltree_exec(struct ast_channel *chan, const char *data)
 		keytree = 0;
 	}
 
-	if (keytree)
+	if (keytree) {
 		ast_verb(3, "DBdeltree: family=%s, keytree=%s\n", family, keytree);
-	else
+	} else {
 		ast_verb(3, "DBdeltree: family=%s\n", family);
+	}
 
-	if (ast_db_deltree(family, keytree))
+	if (ast_db_deltree(family, keytree) < 0) {
 		ast_verb(3, "DBdeltree: Error deleting key from database.\n");
+	}
 
 	return 0;
 }