Fix 2 possible NullPointer occurences

marco

2015-10-17 1aec17636d8c548257cb307f8cc1e41354e00421

 src/main/java/com/gitblit/wicket/pages/propose_git.md

@@ -1,6 +1,6 @@
    git clone ${url}
    cd ${repo}
    git checkout -b ${reviewBranch} ${integrationBranch}
    git checkout -b ${reviewBranch} origin/${integrationBranch}
    ...
    git push --up-stream origin ${reviewBranch}
    git push -u origin ${reviewBranch}