Bug#30029 mysql_upgrade fails for 5.0 -> 5.1.21, 5.1.20 -> 5.1.21 upgrades

 - Change to use '' to quote a string inside another string

scripts/mysql_system_tables.sql

@@ -65,7 +65,7 @@ CREATE TABLE IF NOT EXISTS procs_priv ( Host char(60) binary DEFAULT '' NOT NULL
 
 -- Create general_log if CSV is enabled.
 
-SET @str = IF (@@have_csv = 'YES', 'CREATE TABLE IF NOT EXISTS general_log (event_time TIMESTAMP NOT NULL, user_host MEDIUMTEXT, thread_id INTEGER, server_id INTEGER, command_type VARCHAR(64), argument MEDIUMTEXT) engine=CSV CHARACTER SET utf8 comment="General log"', 'SET @dummy = 0');
+SET @str = IF (@@have_csv = 'YES', 'CREATE TABLE IF NOT EXISTS general_log (event_time TIMESTAMP NOT NULL, user_host MEDIUMTEXT, thread_id INTEGER, server_id INTEGER, command_type VARCHAR(64), argument MEDIUMTEXT) engine=CSV CHARACTER SET utf8 comment=''General log''', 'SET @dummy = 0');
 
 PREPARE stmt FROM @str;
 EXECUTE stmt;
@@ -73,7 +73,7 @@ DROP PREPARE stmt;
 
 -- Create slow_log if CSV is enabled.
 
-SET @str = IF (@@have_csv = 'YES', 'CREATE TABLE IF NOT EXISTS slow_log (start_time TIMESTAMP NOT NULL, user_host MEDIUMTEXT NOT NULL, query_time TIME NOT NULL, lock_time TIME NOT NULL, rows_sent INTEGER NOT NULL, rows_examined INTEGER NOT NULL, db VARCHAR(512), last_insert_id INTEGER, insert_id INTEGER, server_id INTEGER, sql_text MEDIUMTEXT NOT NULL) engine=CSV CHARACTER SET utf8 comment="Slow log"', 'SET @dummy = 0');
+SET @str = IF (@@have_csv = 'YES', 'CREATE TABLE IF NOT EXISTS slow_log (start_time TIMESTAMP NOT NULL, user_host MEDIUMTEXT NOT NULL, query_time TIME NOT NULL, lock_time TIME NOT NULL, rows_sent INTEGER NOT NULL, rows_examined INTEGER NOT NULL, db VARCHAR(512), last_insert_id INTEGER, insert_id INTEGER, server_id INTEGER, sql_text MEDIUMTEXT NOT NULL) engine=CSV CHARACTER SET utf8 comment=''Slow log''', 'SET @dummy = 0');
 
 PREPARE stmt FROM @str;
 EXECUTE stmt;