rpms: add hgext3rd to mercurial.spec
Otherwise build process fails with somethings like this:
RPM build errors:
Installed (but unpackaged) file(s) found:
/usr/lib64/python2.7/site-packages/hgext3rd/__init__.py
/usr/lib64/python2.7/site-packages/hgext3rd/__init__.pyc
/usr/lib64/python2.7/site-packages/hgext3rd/__init__.pyo
make: *** [docker-fedora20] Error 1
--- a/contrib/mercurial.spec Wed Mar 23 10:50:24 2016 -0700
+++ b/contrib/mercurial.spec Wed Mar 23 11:53:11 2016 +0800
@@ -158,4 +158,5 @@
%endif
%{_libdir}/python%{pythonver}/site-packages/%{name}
%{_libdir}/python%{pythonver}/site-packages/hgext
+%{_libdir}/python%{pythonver}/site-packages/hgext3rd
%endif