check empty MYSQL_USER (#835)

Author: hafezdivandari

database/mariadb/create-testing-database.sh

@@ -2,5 +2,10 @@
 
 /usr/bin/mariadb --user=root --password="$MYSQL_ROOT_PASSWORD" <<-EOSQL
     CREATE DATABASE IF NOT EXISTS testing;
+EOSQL
+
+if [ -n "$MYSQL_USER" ]; then
+/usr/bin/mariadb --user=root --password="$MYSQL_ROOT_PASSWORD" <<-EOSQL
     GRANT ALL PRIVILEGES ON \`testing%\`.* TO '$MYSQL_USER'@'%';
 EOSQL
+fi

database/mysql/create-testing-database.sh

@@ -2,5 +2,10 @@
 
 mysql --user=root --password="$MYSQL_ROOT_PASSWORD" <<-EOSQL
     CREATE DATABASE IF NOT EXISTS testing;
+EOSQL
+
+if [ -n "$MYSQL_USER" ]; then
+mysql --user=root --password="$MYSQL_ROOT_PASSWORD" <<-EOSQL
     GRANT ALL PRIVILEGES ON \`testing%\`.* TO '$MYSQL_USER'@'%';
 EOSQL
+fi