Fixed bug when using forceLongFormat on gitDescribe

Setting "forceLongFormat" to true in the "gitDescribe" section of the plugin configuration does not have the desired effect and will not force the long format of the "git.commit.id.describe" property. I've created two new test methods in GitCommitIdMojoIntegrationTest that exposes the bug and made changes that should fix the bug. 

This pull request also includes two changes to two log statements in DescribeCommand. The first fixes a bug and the second adds some extra info.