*: properly compile version into docker images

scripts/git-version

@@ -1,4 +1,5 @@
-#!/bin/bash -e
+#!/bin/sh -e
+# Since this script will be run in a rkt container, use "/bin/sh" instead of "/bin/bash"
 
 # parse the current git commit hash
 COMMIT=`git rev-parse HEAD`
@@ -18,4 +19,4 @@ if [ -n "$(git diff --shortstat 2> /dev/null | tail -n1)" ]; then
     VERSION="${VERSION}-dirty"
 fi
 
-echo $VERSION
+echo $VERSION