Do not change fragments if print activity finishing.

It is possible that we try to switch framents after the print
activity finish method is called. In this state the activity
is going away and trying to perform a fragment operation throws.
Now if we are finishing no fragment opration is performed.

bug:17520007

Change-Id: I0dd935d3cdaeddca31fccf49bd5de97e878abb9d
1 file changed