scripts/getver.sh: Use 'git-rev-parse' to detect if tree lies in Git repository

Path to the Git repository directory can be overriden by using the '$GIT_DIR'
environment variable. This patch improves detection of Git repository by using
'git-rev-parse', which respects '$GIT_DIR' environment variable, instead of just
checking the existence of '.git' directory.

Signed-off-by: Vasilis Tsiligiannis <acinonyx@openwrt.gr>

SVN-Revision: 49165

scripts/getver.sh

@@ -17,7 +17,7 @@ try_svn() {
 }
 
 try_git() {
-	[ -e .git ] || return 1
+	git rev-parse --git-dir >/dev/null 2>&1 || return 1
 	REV="$(git log | grep -m 1 git-svn-id | awk '{ gsub(/.*@/, "", $0); print $1 }')"
 	REV="${REV:+r$REV}"
 	[ -n "$REV" ]