mysql-test/r/sql_mode.result:
  added test for WL 1941 "NO_C_ESCAPE sql_mode"
mysql-test/t/sql_mode.test:
  added test for WL 1941 "NO_C_ESCAPE sql_mode"
sql/mysql_priv.h:
  added MODE_NO_BACKSLASH_ESCAPES
sql/mysqld.cc:
  added mode NO_BACKSLASH_ESCAPES
sql/sql_lex.cc:
  added test for MODE_NO_BACKSLASH_ESCAPES when testing escaped character
sql/sql_yacc.yy:
  added using of "" as escape by default
   in LIKE function if MODE_NO_BACKSLASH_ESCAPES