HCatalog release script does not update version in build.properties

This issue was discovered while testing hcatalog-0.5.0-incubating-candidate-0.

In our source repo we always have a SNAPSHOT version identifier checked in; only when creating release candidates do we specify an actual version number as a build-time argument.

Our release script does not update the version number in build.properties; this causes submodules that depend on hcatalog-core to depend on a snapshot version, instead of the release version.