fix parameters values of the calls

mysql-test/suite/mariabackup/backup_grants.test

@@ -55,7 +55,7 @@ rmdir $targetdir;
 
 GRANT REPLICA MONITOR ON *.* TO backup@localhost;
 --disable_result_log
-exec $XTRABACKUP --defaults-file=$MYSQLTEST_VARDIR/my.cnf --backup --user backup --password xyz --slave-info --target-dir=$targetdir > $MYSQLTEST_VARDIR/tmp/backup.log 2>&1;
+exec $XTRABACKUP --defaults-file=$MYSQLTEST_VARDIR/my.cnf --backup --user=backup --password=xyz --slave-info --target-dir=$targetdir > $MYSQLTEST_VARDIR/tmp/backup.log 2>&1;
 --enable_result_log
 --let SEARCH_PATTERN=  missing required privilege
 --source include/search_pattern_in_file.inc
@@ -68,7 +68,7 @@ REVOKE REPLICA MONITOR ON *.* FROM backup@localhost;
 # --safe-slave-backup requires REPLICATION SLAVE ADMIN, and REPLICA MONITOR
 --disable_result_log
 error 1;
-exec $XTRABACKUP --defaults-file=$MYSQLTEST_VARDIR/my.cnf --backup --user backup --password xyz --safe-slave-backup --target-dir=$targetdir > $MYSQLTEST_VARDIR/tmp/backup.log;
+exec $XTRABACKUP --defaults-file=$MYSQLTEST_VARDIR/my.cnf --backup --user=backup --password=xyz --safe-slave-backup --target-dir=$targetdir > $MYSQLTEST_VARDIR/tmp/backup.log;
 --enable_result_log
 rmdir $targetdir;