Drop Babel from reqs

Not needed per [1].

[1] http://lists.openstack.org/pipermail/openstack-discuss/2020-April/014227.html

Co-Authored-By: Linhui Zhou <df.some@foxmail.com>
Change-Id: Id727819692bb0a3d3ac61f18f421d5430231fb51

babel.cfg

@@ -1 +0,0 @@
-[python: **.py]

requirements.txt

@@ -5,7 +5,7 @@
 # The order of packages is significant, because pip processes them in the order
 # of appearance. Changing the order has an impact on the overall integration
 # process, which may cause wedges in the gate later.
-Babel>=2.5.3 # BSD
+
 botocore>=1.9.7 # Apache-2.0
 cryptography>=2.1.4 # BSD/Apache-2.0
 eventlet>=0.20.0 # MIT

setup.cfg

@@ -48,5 +48,4 @@ input_file = ec2api/locale/ec2api.pot
 
 [extract_messages]
 keywords = _ gettext ngettext l_ lazy_gettext
-mapping_file = babel.cfg
 output_file = ec2api/locale/ec2api.pot