Print SQL connection errors to world log

I had some fun with not being able to connect to any database, while the same settings worked querying the database from a bash console.

This (very small) commit prints the dbcon.ErrorMsg() to the world.log file to aid with database connection-issue debugging.

offtopic: Turns out DreamMaker was looking for libmysql.so which didn't exist on my debian squeeze installation. However libmysql.so.5 existed so I created a libmysql.so symlink and was finally able to connect.