sdk upgrade with playground fails if a merge is necessary

[arif.otyakmaz]

If you upgrade your sdk using playground and a merge is necessary for the sdk, because your sdk has diverged from the sdk you want to upgrade to, playground quits with the following error:
[aoz@beast] openWNS--flowmanagement--1.0Alt: playground.py upgrade
Do you want to upgrade from another branch? (y/N)
Checking for new patches in: ./ ... Found:
You have 4 extra revision(s):
  150 Maciej Muehleisen 2009-01-29 [merge]
      Merged from launchpad

  149 Maciej Muehleisen 2009-01-16 [merge]
      Merged from launchpad

  148 Rainer Schoenen 2009-01-12
      added insource script to bin directory

  147 Daniel Bültmann 2009-01-05
      Fixed setupKDevelop to properly support addOns

You are missing 2 revision(s):
  148 Rainer Schoenen 2009-01-28
      pushMailRecipients.py new

  147 Rainer Schoenen 2009-01-28
      pushMailRecipients.py new

Retrieving new patches for './' ...
An RCS error occured.

The according bzr message is:
[aoz@beast] openWNS--flowmanagement--1.0: bzr pull bzr://bazaar.comnets.rwth-aachen.de/AOZ/openWNS/main/flowmanagement/openWNS--main--1.0/
bzr: ERROR: These branches have diverged. Use the merge command to reconcile them.

bzr info returns:
[aoz@beast] openWNS--flowmanagement--1.0: bzr info
Repository tree (format: dirstate-tags)
Location:
  shared repository: /net/beast1/AOZ/aoz
  repository branch: .

Related branches:
  parent branch: bzr://bazaar.comnets.rwth-aachen.de/openWNS/main/openWNS--main--1.0/

Relevant entries in prohjects.py:
bzrBaseURL = "bzr://bazaar.comnets.rwth-aachen.de/AOZ/openWNS/main/flowmanagement"
bzrBaseAddOnUrl = "bzr://bazaar.comnets.rwth-aachen.de/AOZ/openWNS/addOns/flowmanagement"