Revert "NO-JIRA: bump python bindings post-release version for PyPi"

This reverts commit fc87964419372cb261810a4c9649f7a5b2a5d399.

Turns out that 0.12.2 was never released on PyPi, so no need for the
".post1" designation.
diff --git a/proton-c/bindings/python/setup.py b/proton-c/bindings/python/setup.py
index 2a49f79..8c815cd 100755
--- a/proton-c/bindings/python/setup.py
+++ b/proton-c/bindings/python/setup.py
@@ -366,7 +366,7 @@
             'sdist': CheckSDist}
 
 setup(name='python-qpid-proton',
-      version=bundle.bundled_version_str + ".post1",
+      version=bundle.bundled_version_str,
       description='An AMQP based messaging library.',
       author='Apache Qpid',
       author_email='proton@qpid.apache.org',