Bug#28234 - global/session scope - documentation vs implementation

Post-pushbuild fix.

- Windows does not have 'socket' system variable.
- Compiler warning in sql/slave.cc

mysql-test/r/variables.result:
  Bug#28234 - global/session scope - documentation vs implementation
  Updated test result.
mysql-test/t/variables.test:
  Bug#28234 - global/session scope - documentation vs implementation
  Removed test for 'socket' variable. Windows doesn't have it.
sql/slave.cc:
  Bug#28234 - global/session scope - documentation vs implementation
  Changed type of constant to avoid a compiler warning.

mysql-test/r/variables.result

@@ -1325,19 +1325,6 @@ ERROR HY000: Variable 'skip_show_database' is a read only variable
 SET @@global.skip_show_database= true;
 ERROR HY000: Variable 'skip_show_database' is a read only variable
 #
-SHOW VARIABLES like 'socket';
-Variable_name	Value
-socket	#
-SELECT @@session.socket;
-ERROR HY000: Variable 'socket' is a GLOBAL variable
-SELECT @@global.socket;
-@@global.socket
-#
-SET @@session.socket= 'x';
-ERROR HY000: Variable 'socket' is a read only variable
-SET @@global.socket= 'x';
-ERROR HY000: Variable 'socket' is a read only variable
-#
 SHOW VARIABLES like 'thread_stack';
 Variable_name	Value
 thread_stack	#

mysql-test/t/variables.test

@@ -1067,18 +1067,6 @@ SET @@global.skip_show_database= true;
 #
 --echo #
 --replace_column 2 #
-SHOW VARIABLES like 'socket';
---error ER_INCORRECT_GLOBAL_LOCAL_VAR
-SELECT @@session.socket;
---replace_column 1 #
-SELECT @@global.socket;
---error ER_INCORRECT_GLOBAL_LOCAL_VAR
-SET @@session.socket= 'x';
---error ER_INCORRECT_GLOBAL_LOCAL_VAR
-SET @@global.socket= 'x';
-#
---echo #
---replace_column 2 #
 SHOW VARIABLES like 'thread_stack';
 --error ER_INCORRECT_GLOBAL_LOCAL_VAR
 SELECT @@session.thread_stack;

sql/slave.cc

@@ -288,7 +288,7 @@ static void print_slave_skip_errors(void)
     10 characters must be sufficient for a number plus {',' | '...'}
     plus a NUL terminator. That is a max 6 digit number.
   */
-  const int MIN_ROOM= 10;
+  const size_t MIN_ROOM= 10;
   DBUG_ENTER("print_slave_skip_errors");
   DBUG_ASSERT(sizeof(slave_skip_error_names) > MIN_ROOM);
   DBUG_ASSERT(MAX_SLAVE_ERROR <= 999999); // 6 digits