Removed version.number / vagrant-cloud post-processor

A few weeks ago ... the version.number changed from an integer to a
semver based string.

I guess version.number and version.version are equals now. So
version.version can be used.

This commit should fix #1735
Merge pull request #1789 from grafjo/patch-1

Changed type of version.number / vagrant-cloud post-processor
Fixes #1735