fedora.spec: omit version in header and put it into the changelog

packaging/fedora/snapd.spec

@@ -48,7 +48,6 @@
 %global snappy_svcs     snapd.service snapd.socket snapd.autoimport.service snapd.refresh.timer snapd.refresh.service
 
 Name:           snapd
-Version:        2.27
 Release:        0%{?dist}
 Summary:        A transactional software package manager
 Group:          System Environment/Base
@@ -637,7 +636,7 @@ fi
 
 %changelog
 * Thu Jul 13 2017 Michael Vogt <mvo@ubuntu.com> - 2.27~rc3
-- New upstream release:
+- New upstream release 2.27~rc3:
  - store: talk to api.snapcraft.io for purchases
  - hooks: support for install and remove hooks
  - packaging: fix Fedora support