mysql: Don't attempt to dump performance_schema database (Redmine#3741).

Locking its tables require privileges the 'debian-sys-maint'@'localhost' user is
generally not granted.

ChangeLog

@@ -14,6 +14,8 @@ version 1.0 -- UNRELEASED
 	   example.dup.
 	 . Add support for RackSpace's CloudFiles.
 	   Thanks to Yuval Kogman <nothingmuch@woobling.org> for the patch.
+	mysql:
+	 . Don't attempt to dump performance_schema database (Redmine#3741).
 
 version 0.9.10 -- September 23, 2011
     backupninja changes

handlers/mysql.in

@@ -256,7 +256,7 @@ then
    for db in $databases
    do
       DUMP_BASE="$MYSQLDUMP $defaultsfile $sqldumpoptions"
-      if [ "$db" = "information_schema" ]
+      if [ "$db" = "information_schema" ] || [ "$db" = "performance_schema" ]
       then
          DUMP_BASE="${DUMP_BASE} --skip-lock-tables"
       fi