build: Use git describe --always

Add --always flag to "git describe" command to get a build identifier
even if one checks out the repo with a depth parameter that prunes out
the last tagged version.

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
(cherry picked from commit a3c93bd81d)

scripts/buildversion.py

@@ -36,7 +36,7 @@ def git_version():
     if not os.path.exists('.git'):
         logging.debug("No '.git' file/directory found")
         return ""
-    ver = check_output("git describe --tags --long --dirty").strip()
+    ver = check_output("git describe --always --tags --long --dirty").strip()
     logging.debug("Got git version: %s" % (repr(ver),))
     return ver