update modulfile version to conform to semver

The current version specified in the Modulefile
does not conform to semantic versioning as specified
by http://semver.org/ and is a requirement for all
versioned puppet modules.

This commit removes the trailing 'a' so that the module
conforms with semantic versioning.
Merge pull request #5 from bodepd/fix_module_version

update modulfile version to conform to semver