Fix broken link to squash icon used in commandImages extension
Fix broken link to squash icon used in commandImages extension

We have a new png squash icon so use it to fix broken link to the old
gif icon which was deleted.

Change-Id: I1b0c626094ac4df1de4a14605dc74a059d7922d1
Signed-off-by: Matthias Sohn <446760a3fbea85cd5f8f4f5c3de304fe3a38014f@sap.com>

paulvi/egit,SmithAndr/egit,wdliu/egit,paulvi/egit,wdliu/egit,collaborative-modeling/egit,SmithAndr/egit,collaborative-modeling/egit