Include class name when showing exceptions

Hi,
I've been using the 7.x-2.6rc1 branch to run a fairly large migration set from mssql. Every once and a while, a change on either our side or the source side leads to failures.

Right now we see something along the lines of "Migration failed with source plugin exception: mssql_query(): messag .. " in drush. It would be great if we could see the class name that failed it would really help us with debuging.

So

try {
      $this->source->rewind();
    }
    catch (Exception $e) {
      self::displayMessage(
        t('Migration failed with source plugin exception: !e',
          array('!e' => $e->getMessage())));
      return MigrationBase::RESULT_FAILED;
    }

Would be

try {
      $this->source->rewind();
    }
    catch (Exception $e) {
      self::displayMessage(
        t('Migration for !class failed with source plugin exception: !e',
          array('!e' => $e->getMessage(), '!class' => get_class($this))));
      return MigrationBase::RESULT_FAILED;
    }

I can try make a patch if anyone thinks this is a good idea.