BUG#12984 mysqltest.test: different output from "exec NonExistsinfComamdn"

 - Improved solution

mysql-test/r/mysqltest.result

@@ -179,6 +179,7 @@ source database
 echo message echo message
 
 mysqltest: At line 1: Empty variable
+mysqltest: At line 1: command "false" failed
 mysqltest: At line 1: Missing argument in exec
 MySQL
 "MySQL"
@@ -300,6 +301,7 @@ mysqltest: At line 1: First argument to dec must be a variable (start with $)
 mysqltest: At line 1: End of line junk detected: "1000"
 mysqltest: At line 1: Missing arguments to system, nothing to do!
 mysqltest: At line 1: Missing arguments to system, nothing to do!
+mysqltest: At line 1: system command 'false' failed
 test
 test2
 test3

mysql-test/t/mysqltest.test

@@ -426,9 +426,8 @@ echo ;
 # ----------------------------------------------------------------------------
 
 # Illegal use of exec
-# Disabled, some shells prints the failed command regardless of pipes
-#--error 1
-#--exec echo "--exec ';' 2> /dev/null" | $MYSQL_TEST 2>&1
+--error 1
+--exec echo "--exec false" | $MYSQL_TEST 2>&1
 
 --error 1
 --exec echo "--exec " | $MYSQL_TEST 2>&1
@@ -675,9 +674,8 @@ system echo "hej" > /dev/null;
 --exec echo "system;" | $MYSQL_TEST 2>&1
 --error 1
 --exec echo "system $NONEXISTSINFVAREABLI;" | $MYSQL_TEST 2>&1
-# Disabled, some shells prints the failed command regardless of pipes
-#--error 1
-#--exec echo "system NonExistsinfComamdn 2> /dev/null;" | $MYSQL_TEST 2>&1
+--error 1
+--exec echo "system false;" | $MYSQL_TEST 2>&1
 
 --disable_abort_on_error
 system NonExistsinfComamdn;