Add comment explaining gitpython requirement

Also clean up some tabs.

Change-Id: If641a164c21dc7b13d48548558ea16e0c0a0b400
diff --git a/tests/fixtures/fake_git.sh b/tests/fixtures/fake_git.sh
index e1734be..5b787b7 100755
--- a/tests/fixtures/fake_git.sh
+++ b/tests/fixtures/fake_git.sh
@@ -3,12 +3,12 @@
 echo $*
 case "$1" in
     clone)
-	dest=$3
-	mkdir -p $dest/.git
-	;;
+        dest=$3
+        mkdir -p $dest/.git
+        ;;
     version)
-	echo "git version 1.0.0"
-	exit 0
-	;;
+        echo "git version 1.0.0"
+        exit 0
+        ;;
 esac
 sleep 30