Delete pid file when crashing after timeout with unacked trx

Summary:
If rpl_semi_sync_master_crash_if_active_trxs = true, the server crashes after a
timeout if there are any active unacked transactions. mysqld_safe expects the
pid file to be deleted if the expectation is to not bring the intance back up
again. This change deletes the pid file before crashing on this condition.

Squash with D5841339

Reviewed By: Tema

Differential Revision: D7747659

fbshipit-source-id: a94df24

Author: abhinav04sharma

plugin/semisync/semisync_master.cc

@@ -16,6 +16,7 @@
 
 
 #include "semisync_master.h"
+#include "mysqld.h"
 #if defined(ENABLED_DEBUG_SYNC)
 #include "debug_sync.h"
 #include "sql_class.h"
@@ -913,6 +914,7 @@ int ReplSemiSyncMaster::switch_off()
   {
     sql_print_error("Force shutdown: Semi-sync master is being switched off "
                     "while there are active un-acked transactions");
+    delete_pid_file(MYF(MY_WME));
     exit(0);
   }
 

sql/mysqld.cc

@@ -1582,7 +1582,6 @@ static void create_shutdown_file();
 static int delete_shutdown_file();
 static void mysqld_exit(int exit_code) MY_ATTRIBUTE((noreturn));
 #endif
-static void delete_pid_file(myf flags);
 
 
 #ifndef EMBEDDED_LIBRARY
@@ -12182,7 +12181,7 @@ static int delete_shutdown_file()
   @param  flags  file operation flags
 */
 
-static void delete_pid_file(myf flags)
+void delete_pid_file(myf flags)
 {
 #ifndef EMBEDDED_LIBRARY
   File file;

sql/mysqld.h

@@ -252,6 +252,7 @@ bool is_secure_file_path(char *path);
 bool is_mysql_datadir_path(const char *path);
 void dec_connection_count_locked();
 void dec_connection_count();
+void delete_pid_file(myf flags);
 
 // These are needed for unit testing.
 void set_remaining_args(int argc, char **argv);