repopick.py: don't handle square brackets during topic picking

ignore the square brackets for now, this is done for the actual cherry-picking
in line 286. We can revisit this if we come accross an instance where it is
actually needed

Change-Id: I318ef3e943c31e92245075d7683361898590fbfc
Merge "repopick.py: don't handle square brackets during topic picking" into pac-4.4