scripts/getver.sh: Fix revision numbering (for Github-based repo)

Fix Chaos Calmer revision numbering. CC has been stuck at r49389 since
the final move to Github as revision number evaluation has still been
based on git-svn-id that is not found in the new original Github commits.
So the revision has been stuck at last svn commit in June.

This patch
* copies the git revision logic from master and uses v15.05.1 tag
  as the base. As the last commit with a known svn revision 49389 was
  cb4f071 with tag+135, use 49254 as the adjustment. That produces
  r49461 for the current 8a1f7c9

* removes the useless svn evaluation (similarly as in master).

Signed-off-by: Hannu Nyman <hannu.nyman@iki.fi>

scripts/getver.sh

@@ -17,9 +17,9 @@ try_svn() {
 }
 
 try_git() {
-	[ -e .git ] || return 1
-	REV="$(git log | grep -m 1 git-svn-id | awk '{ gsub(/.*@/, "", $0); print $1 }')"
-	REV="${REV:+r$REV}"
+	git rev-parse --git-dir >/dev/null 2>&1 || return 1
+	REV="$(git describe --tags | sed "s/v15.05.1-\([0-9]*\)-.*/\1/g")"
+	REV="${REV:+r$((REV+49254))}"
 	[ -n "$REV" ]
 }
 
@@ -30,5 +30,5 @@ try_hg() {
 	[ -n "$REV" ]
 }
 
-try_version || try_svn || try_git || try_hg || REV="unknown"
+try_version || try_git || try_hg || REV="unknown"
 echo "$REV"