made the mysql query compatible with v5.7

Updated the query according to 
https://dev.mysql.com/doc/refman/5.6/en/resetting-permissions.html
and
https://dev.mysql.com/doc/refman/5.7/en/set-password.html

to make it compatible with both mysql v5.6 and v5.7

bin/v-change-database-host-password

@@ -42,9 +42,9 @@ subj="v-change-database-host-password $*"
 
 case $type in
     mysql)    mysql_connect $host;
-              query="USE mysql; UPDATE user SET"
-              query="$query password=PASSWORD('$dbpass')"
-              query="$query WHERE User='$dbuser';"
+              query="SET PASSWORD FOR"
+              query="$query '$dbuser'@'localhost'"
+              query="$query = PASSWORD('$dbpass');"
               query="$query FLUSH PRIVILEGES;"
               mysql_query "$query" ;
               if [ "$dbuser" == "root" ]; then