builtin/rm.c: consolidate error reporting for removing submodules

We have two (not identical) copies of error reporting when
attempting to remove submodules that have their repositories
embedded within them.  Add a helper function so that we do not have
to repeat similar error messages with subtly different wording
without a good reason.

Noticed by Jiang Xin.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
contrib/subtree: Fix make install target

If the libexec directory doesn't exist, git-subtree gets installed as
$prefix/share/libexec/git-core file. This patch creates the directory
before installing git-subtree file into it.

Signed-off-by: Michal Sojka <sojkam1@fel.cvut.cz>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
t5540/5541: smart-http does not support "--force-with-lease"

The push() method in remote-curl.c is not told and does not pass the
necessary information to underlying send-pack, so this extension
does not yet work.  Leave a note in the test suite.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
Merge branch 'jx/clean-interactive'

* jx/clean-interactive:
  git-clean: implement partial matching for selection
  Documentation/git-clean: fix description for range
Merge branch 'ma/hg-to-git'

* ma/hg-to-git:
  hg-to-git: --allow-empty-message in git commit
Merge branch 'lf/echo-n-is-not-portable'

* lf/echo-n-is-not-portable:
  Avoid using `echo -n` anywhere
Merge branch 'jc/rm-submodule-error-message'

Consolidate two messages phrased subtly differently without a good
reason.

* jc/rm-submodule-error-message:
  builtin/rm.c: consolidate error reporting for removing submodules
Merge branch 'ms/subtree-install-fix'

* ms/subtree-install-fix:
  contrib/subtree: Fix make install target
Merge branch 'ob/typofixes'

* ob/typofixes:
  many small typofixes
Git 1.8.4-rc1

Signed-off-by: Junio C Hamano <gitster@pobox.com>
Merge branch 'jc/rm-submodule-error-message' into next

Consolidate two messages phrased subtly differently without a good
reason.

* jc/rm-submodule-error-message:
  builtin/rm.c: consolidate error reporting for removing submodules
Merge branch 'ms/subtree-install-fix' into next

* ms/subtree-install-fix:
  contrib/subtree: Fix make install target
Merge branch 'jc/push-cas' into next

Add a new test as a reminder that smart-http does not grok the
option (yet).

* jc/push-cas:
  t5540/5541: smart-http does not support "--force-with-lease"
Sync with v1.8.4-rc1

* master:
  Git 1.8.4-rc1