GIT: Switches to shallow clones

Goes from full git clones to a shallow clone (depth = 1) to reduce space
usage.

Change-Id: Ibdbd03ec319deb22ec21d971e1ce5ba7e678ec1c
Signed-off-by: Matthew Dalzell <matthew.dalzell@arm.com>
diff --git a/run-build.sh b/run-build.sh
index 5a9e6db..47b9acd 100755
--- a/run-build.sh
+++ b/run-build.sh
@@ -33,7 +33,8 @@
         REPO_REFSPEC="$(echo "${repo}" | awk -F ';' '{print $2}')"
 
         if [ ! -z "$REPO_REFSPEC" ] ; then
-            git_checkout $REPO_PATH $REPO_REFSPEC
+            echo "Refspec was not pulled correctly"
+            exit 1
         fi
     done
 }