Add the ability to load a metastore snapshot file.

This patch includes the following changes:
  - Modifies buildall to accept a hive metastore snapshot file as an argument.
  - Adds a script to load the hive metastore snapshot.

Change-Id: I7b9fc5b0643afe62fd4739a81eaa3bf9af1630da
Reviewed-on: http://gerrit.sjc.cloudera.com:8080/5510
Reviewed-by: Ishaan Joshi <ishaan@cloudera.com>
Tested-by: jenkins