Fix inverted conditionals in setup_develop

This fixes regressions introduced by:
    Change-Id: Ic97e68348f46245b271567893b447fcedbd7bd6e
    ("Handle non-zero exit code from git diff")

Change-Id: I053a292c287f3035eef37db2264eda06a170f9bc
Closes-Bug: 1287513
Merge "Fix inverted conditionals in setup_develop"