DNN-4928 Fix error when editing JavaScript Library extension

When a JavaScript Library extension has a dependency on a library, and the
version of that dependency only has two digits (e.g. 1.7), then there is an
exception that is thrown when trying to format the version

This commit checks the version before formatting it, so that the exception
won't be thrown.
Merge pull request #79 from bdukes/two-digit-version

DNN-4928 Fix error when editing JavaScript Library extension