atomictempfile: make close() consistent with other file-like objects. The usual contract is that close() makes your writes permanent, so atomictempfile's use of close() to *discard* writes (and rename() to keep them) is rather unexpected. Thus, change it so close() makes things permanent and add a new discard() method to throw them away. discard() is only used internally, in __del__(), to ensure that writes are discarded when an atomictempfile object goes out of scope. I audited mercurial.*, hgext.*, and ~80 third-party extensions, and found no one using the existing semantics of close() to discard writes, so this should be safe.

posix: check for executable bits on files identified by findexe function

subrepo: fix cloning of repos from urls without slash after host (issue2970) This fixes a regression introduced with the new url handling in 1.9. This should perhaps be fixed in the url class instead, but that might be too invasive for a stable bugfix.

merge with stable