Snap: Derive version from git describe

snap/snapcraft.yaml

@@ -116,14 +116,11 @@ parts:
     source: .
     override-pull: |
       snapcraftctl pull
-      if [ -d .git ]; then
-        revision=$(git svn find-rev HEAD)
-      else
-        revision=$(svn --xml info | grep revision=\" | tail -1 | cut -d\" -f2)
+      if ! git describe --dirty; then
+        rc2_parent="a8789f7"
+        git -c user.name="snapcraft" -c user.email="snapcraft@local.build" tag -a "0.7RC2" -m "stand-in tag" "$rc2_parent"
       fi
-      version=$(cat sources/qet.h |grep "const QString version" |  cut -d\" -f2 | cut -d\" -f1)
-      displayed_version=$(cat sources/qet.h | grep displayedVersion |  cut -d\" -f2 | cut -d\" -f1)
-      snap_version="$displayed_version~svn$revision"
+      snap_version=$(git describe --dirty | sed -e 's/-/+git/;y/-/./')
       modified_displayed_version=$snap_version".snap"
       sed -i -E "s|const QString displayedVersion =.*|const QString displayedVersion =\"$modified_displayed_version\";|" sources/qet.h
       snapcraftctl set-version "$snap_version"
@@ -139,8 +136,6 @@ parts:
       - libkf5widgetsaddons-dev
       - libkf5coreaddons-dev
       - git
-      - git-svn
-      - subversion
     stage-packages: 
       - qtwayland5
       - qt5-gtk-platformtheme