Refactored smells out of query_runner/connection.rb

Smells reported by reek:

Before:

 1: NoBrainer::QueryRunner::Connection has no descriptive comment
    (IrresponsibleModule)
 5: NoBrainer::QueryRunner::Connection#call has the variable name 'e'
    (UncommunicativeVariableName)

After:

 1: NoBrainer::QueryRunner::Connection has no descriptive comment
    (IrresponsibleModule)

Notes:

Wasn't exactly sure how to describe the class, so I left that smell
alone.