Added rpl_status. This is a midway commit to be able to pull so I can save

myself a run of compile-pentium-debug. I have not even tried to compile the 
new code


sql/Makefile.am:
  added repl_failsafe.*
sql/mysqld.cc:
  added Rpl_status
sql/sql_show.cc:
  added rpl_status
sql/structs.h:
  rpl_status

sql/structs.h

@@ -140,6 +140,7 @@ enum SHOW_TYPE { SHOW_LONG,SHOW_CHAR,SHOW_INT,SHOW_CHAR_PTR,SHOW_BOOL,
 		 ,SHOW_SSL_CTX_SESS_TIMEOUTS, SHOW_SSL_CTX_SESS_CACHE_FULL
 		 ,SHOW_SSL_GET_CIPHER_LIST
 #endif /* HAVE_OPENSSL */
+		 ,SHOW_RPL_STATUS
 };
 
 enum SHOW_COMP_OPTION { SHOW_OPTION_YES, SHOW_OPTION_NO, SHOW_OPTION_DISABLED};