Added instructions for upgrading a database/ cluster of databases from 1.9 to 2.0
Adds test for exceptions thrown when properties are missing
Editing upgrade instructions.
Remove confusing deprecation message

Deprecation message is a little premature as we don't have
a compelling alternative.  Also, cleans up the docs, for clarity.

Fixes #1531
Merge pull request #1550 from simpsonjulian/installer-fixes-fixes

Remove confusing deprecation message