Refactored smells out of query_runner/write_error.rb

Smells reported by reek:

Before:

 1: NoBrainer::QueryRunner::WriteError has no descriptive comment
    (IrresponsibleModule)
15: NoBrainer::QueryRunner::WriteError#call calls e.message twice
    (DuplicateMethodCall)
 8: NoBrainer::QueryRunner::WriteError#call calls is_write_query?(env)
    twice (DuplicateMethodCall)
13: NoBrainer::QueryRunner::WriteError#call has the variable name
    'e' (UncommunicativeVariableName)
22: NoBrainer::QueryRunner::WriteError#is_write_query? doesn't depend
    on instance state (UtilityFunction)
22: NoBrainer::QueryRunner::WriteError#is_write_query? refers to env
    more than self (FeatureEnvy)

After:

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

Notes:

Broke out a class utility method to normalize error messages