MDEV-20505: Server crash on startup beacuse of bad wsrep configuration

Problem was that if user used bad wsrep configuration
we call unireg_abort and in wsrep case there is check
to wsrep_server_state that might not yet be initialized.
Fixed by checking that wsrep_server_state is initialized
before checking it's state.

Changes to be committed:
	modified:   sql/mysqld.cc
	modified:   sql/wsrep_server_state.h

1 files changed, 6 insertions, 0 deletions

diff --git a/sql/wsrep_server_state.h b/sql/wsrep_server_state.h
index 34ff4105180..1ef937300f6 100644
--- a/sql/wsrep_server_state.h
+++ b/sql/wsrep_server_state.h
@@ -35,11 +35,17 @@ public:
                         const wsrep::gtid& initial_position,
                         int max_protocol_version);
   static void destroy();
+
   static Wsrep_server_state& instance()
   {
     return *m_instance;
   }
 
+  static bool is_inited()
+  {
+    return (m_instance != NULL);
+  }
+
   static wsrep::provider& get_provider()
   {
     return instance().provider();