Install git-shell in bindir, too

/etc/passwd shell field must be something execable, you can't enter
"/usr/bin/git shell" there. git-shell must be present as a separate
executable, or it is useless.

Signed-off-by: Tommi Virtanen <tv@eagain.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Makefile

@@ -1355,7 +1355,7 @@ install: all
 	$(INSTALL) -d -m 755 '$(DESTDIR_SQ)$(bindir_SQ)'
 	$(INSTALL) -d -m 755 '$(DESTDIR_SQ)$(gitexec_instdir_SQ)'
 	$(INSTALL) $(ALL_PROGRAMS) '$(DESTDIR_SQ)$(gitexec_instdir_SQ)'
-	$(INSTALL) git$X git-upload-pack$X git-receive-pack$X git-upload-archive$X '$(DESTDIR_SQ)$(bindir_SQ)'
+	$(INSTALL) git$X git-upload-pack$X git-receive-pack$X git-upload-archive$X git-shell$X '$(DESTDIR_SQ)$(bindir_SQ)'
 	$(MAKE) -C templates DESTDIR='$(DESTDIR_SQ)' install
 	$(MAKE) -C perl prefix='$(prefix_SQ)' DESTDIR='$(DESTDIR_SQ)' install
 ifndef NO_TCLTK