Add requirement for python2-pillow

Some of zbar's python scripts require python2-pillow, in order
to display images.

Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

zbar.spec

@@ -60,7 +60,7 @@ scanning widget.
 %package pygtk
 Group: Development/Libraries
 Summary: Bar code reader PyGTK widget
-Requires: pygtk2, %{name}-gtk = %{version}-%{release}
+Requires: pygtk2, python2-pillow, %{name}-gtk = %{version}-%{release}
 
 %description pygtk
 This package contains a bar code scanning widget for use in GUI