Openshift checkouts do not include git submodule trees

[darkmuggle]

Related to #320, Openshift 3.9 is not copying the submodules, causing Mantle builds to fail.

Example:

+ test -f mantle/README.md
+ '[' -n '' ']'
+ '[' -n '' ']'
+ make
cd mantle && ./build ore kola kolet
fatal: No names found, cannot describe anything.
make: *** [Makefile:12: mantle] Error 128
Removing intermediate container 3bfa9eaa6497
error: build error: The command '/bin/sh -c ./build.sh make_and_makeinstall' returned a non-zero code: 2
```

Further, the test for `mantle/README.md` is insufficient since the build checks the status for the Git tree. 

[cgwalters]

We still have the logic from 7124ada though - is that not kicking in?

[cgwalters]

Ah, right I see your commit. Might as well squash this bit in then:

diff --git a/build.sh b/build.sh
index 0d01b8cf..89af74d9 100755
--- a/build.sh
+++ b/build.sh
@@ -84,13 +84,6 @@ install_rpms() {
 }
 
 _prep_make_and_make_install() {
-    # Work around https://github.com/coreos/coreos-assembler/issues/27
-    if ! test -d .git; then
-        (git config --global user.email [email protected]
-         git init && git add . && git commit -a -m 'dummy commit'
-         git tag -m tag dummy-tag) >/dev/null
-    fi
-
     # TODO: install these as e.g.
     # /usr/bin/ostree-releng-script-rsync-repos
     mkdir -p /usr/app/