STYLE: Remove obsolete logic method.

As discussed in [1], this method was used only in the initial version
of the module and can be removed.

[1] https://github.com/fedorov/MultiVolumeExplorer/pull/22#issuecomment-47184951
Merge pull request #23 from jcfr/remove-obslete-logic-method

STYLE: Remove obsolete logic method.