[FIX] packaging: oversight of polib in setup.py

Since commit 632fa04, polib is used instead of a custom pofile
reader. The setup.py file was forgotten in packaging, leading to a
faulty source package.

closes odoo#34585

Signed-off-by: Christophe Monniez (moc) <moc@odoo.com>

setup.py

@@ -37,6 +37,7 @@
         'ofxparse',
         'passlib',
         'pillow',  # windows binary http://www.lfd.uci.edu/~gohlke/pythonlibs/
+        'polib',
         'psutil',  # windows binary code.google.com/p/psutil/downloads/list
         'psycopg2 >= 2.2',
         'pydot',