WL# 2094 Federated Storage Handler

This changeset/patch is on top of changesets 1.1814 and 1.1846 
(for bugs 8033 and 8065) and now fixes bug 8535.

These changes have been built and tested successfully on build.mysql.com

handler.cc:
  Added hooks for federated_db_init() and federated_db_end(), 
  as done with ha_archive_db does, per suggestion by Ingo in
  code review of patch 1.1846.
ha_federated.h:
  declaration of federated_db_init() and federated_db_end()
ha_federated.cc:
  - Fixed some indentation problems from indent-ex (mainly to do with
    cases where "variablename += value"
  - Added federated_db_init() and federated_db_end(), as done with
    archive, which also handler more elegantly one of the memory leaks
    from bug 8033 where the federated_mutex was not freed
  - Removed extrenous debug messages in parse_url()
  - Fixed bug 8535, caused by NULL being quoted in write_row. This used to
    work (incorrectly) but a recent change was made in the server that 
    exposed this

sql/ha_federated.h

@@ -174,3 +174,6 @@ public:
   THR_LOCK_DATA **store_lock(THD *thd, THR_LOCK_DATA **to,
                              enum thr_lock_type lock_type);     //required
 };
+
+bool federated_db_init(void);
+bool federated_db_end(void);

sql/handler.cc

@@ -364,6 +364,16 @@ int ha_init()
       opt_using_transactions=1;
   }
 #endif
+#ifdef HAVE_FEDERATED_DB
+  if (have_federated_db == SHOW_OPTION_YES)
+  {
+    if (federated_db_init())
+    {
+      have_federated_db= SHOW_OPTION_DISABLED;
+      error= 1;
+    }
+  }
+#endif
 #ifdef HAVE_ARCHIVE_DB
   if (have_archive_db == SHOW_OPTION_YES)
   {
@@ -405,6 +415,10 @@ int ha_panic(enum ha_panic_function flag)
   if (have_ndbcluster == SHOW_OPTION_YES)
     error|=ndbcluster_end();
 #endif
+#ifdef HAVE_FEDERATED_DB
+  if (have_federated_db == SHOW_OPTION_YES)
+    error|= federated_db_end();
+#endif
 #ifdef HAVE_ARCHIVE_DB
   if (have_archive_db == SHOW_OPTION_YES)
     error|= archive_db_end();