imputils Importer._process_result():
    remove name from modules dict if exec fails.

This is what all the builtin importers do now, new in 2.4.

From SF patch #852334.

(From SF patch #810751)

[#636769] Fix for major rexec bugs

* Lib/rexec.py
  (FileBase): Added 'xreadlines' and '__iter__' to allowed file methods.
  (FileWrapper.__init__): Removed unnecessary self.f variable, which gave
  direct access to the file object.
  (RExec): Added 'xreadlines' and '_weakref' to allowed modules.
  (RExec.r_open): Convert string subclasses to a real string classes
  before doing comparisons with mode parameter.

* Lib/ihooks.py
  (BasicModuleImporter.import_module/reload/unload): Convert the module
  name to a real string before working with it.
  (ModuleImporter.import_module/import_it/reload): Convert the module
  name to a real strings before working with it.

* Misc/NEWS
  Document the change.

fixed typo in ihooks docstring

ihooks.ModuleLoader does not implement reload(mod) correctly:
If mod has already been loaded by ModuleLoader, it has
been returned from a cache. Added an additional parameter
to import_it() to force reloading.

didn't want to commit until it had been tested.  I presume that it
works in Grail.)

ModuleLoader.load_module!  (Thanks to Daniel Larsson who complained
about this.)

load_module(), to mimick the behavior of imp more closely.

some of our modules for special purposes (e.g. rexec).