Merge branch 'nd/clear-gitenv-upon-use-of-alias'

d95138e6 (setup: set env $GIT_WORK_TREE when work tree is set, like $GIT_DIR, 2015-06-26) attempted to work around a glitch in alias handling by overwriting GIT_WORK_TREE environment variable to affect subprocesses when set_git_work_tree() gets called, which resulted in a rather unpleasant regression to "clone" and "init". Try to address the same issue by always restoring the environment and respawning the real underlying command when handling alias. * nd/clear-gitenv-upon-use-of-alias: run-command: don't warn on SIGPIPE deaths git.c: make sure we do not leak GIT_* to alias scripts setup.c: re-fix d95138e (setup: set env $GIT_WORK_TREE when .. git.c: make it clear save_env() is for alias handling only