sanitize the version number of the ubuntu-core snap

debian/changelog

@@ -1,10 +1,14 @@
-livecd-rootfs (2.420) UNRELEASED; urgency=medium
+livecd-rootfs (2.420ubuntu1) UNRELEASED; urgency=medium
 
+  [ Łukasz 'sil2100' Zemczak ]
   * Remove the ubuntu-pd project from the scripts
   * Add instead an ubuntu-touch-custom project for custom re-builds of
     ubuntu-touch 
 
- -- Łukasz 'sil2100' Zemczak <lukasz.zemczak@ubuntu.com>  Wed, 06 Jul 2016 12:57:44 +0200
+  [ Oliver Grawert ]
+  * sanitize the version number of the ubuntu-core snap
+
+ -- Oliver Grawert <ogra@ubuntu.com>  Tue, 19 Jul 2016 13:59:16 +0200
 
 livecd-rootfs (2.419) yakkety; urgency=medium
 

live-build/auto/build

@@ -257,7 +257,7 @@ if [ "$PROJECT:$SUBPROJECT" = "ubuntu-core:system-image" ]; then
             mkdir -p $rootfs/$dir
         done
 
-        VERSION="$(lsb_release -r -s)+$(date +20%y%m%d.%H-%M)"
+        VERSION="$(lsb_release -r -s)"
 
         CORENAME="ubuntu-core"
         cat > $rootfs/meta/snap.yaml <<EOF