fix: Remove MENDER_CONVERT_VERSION definition from mender-convert

This was a regression introduced as a merge error on my behalf. This was already
moved out of the `mender-convert` script by Dell Green, and into
`modules/git.sh` which handles the version parsing in the
`docker-mender-convert` script.

Changelog: None

Signed-off-by: Ole Petter <ole.orhagen@northern.tech>

mender-convert

@@ -29,8 +29,6 @@ declare -a overlays=()        # [Dummy] Needed in parse_cli_options, not here
 declare -a configs=()        # [Dummy] Needed in parse_cli_options, not here
 ###############################################################################
 
-MENDER_CONVERT_VERSION=$(git describe --tags --dirty --exact-match 2>/dev/null || git rev-parse --short HEAD)
-
 function show_help() {
   cat << EOF
 mender-convert