Fix version-tag for rest-client/pom.xml

- the BROOKLYN_VERSION marker needs to either be same line or
  previous line, but was on the line after...
fix change-version for multiple occurrences on line

- Previously, if had:
    OLDVER blah OLDVER // BROOKLYN_VERSION 
  it would only replace the first OLDVER
- Now it replaces all occurrences of OLDVER on that line.
  Does it with an ugly `while <grep>; do sed ...; done`
  because getting /g to work would be extremely hard based on the 
  pattern matching used.
Merge pull request #870 from aledsage/fix/version-updating

Fix version updating