Enhance how we look for the sql file in {import,export}_db_dump
Enhance how we look for the sql file in {import,export}_db_dump

Instead of expecting just one more argument (like staging in 'cap staging
mysql:import_db_dump), look for the index of the task we're requesting and add
one to it.. This way wherever the task has been added to the call, we are able
to fetch the file name from the command line string

refs #1
@10m

TechnoGate/capistrano-exts