add an error message for cloning private repos
handle errors while building
Remember repoUrl if append .git to it.
Merge pull request #1982 from dart-lang/git_rem_repo

Remember repoUrl if append .git to it.
Fix null check in git commit.
Merge pull request #1988 from dart-lang/fix_commit_null

Fix null check in git commit.
nit
Merge pull request #1979 from devoncarew/devoncarew_clone_private

add an error message for cloning private repos
Merge branch 'master' into devoncarew_handle_analysis_errors
Merge pull request #1980 from devoncarew/devoncarew_handle_analysis_errors

handle errors while building
Merge branch 'master' into devoncarew_cancel_deploy
cleaned up cancel code