several decorators don't work with bound methods

[Gary Wilson]

Similar to #4376, there are several other decorators that don't work with bound methods. A few that I noticed were cache_page, cache_control, and never_cache from django.views.decorators.cache. cache_page uses decorator_from_middleware, and other decorators created with this "decorator generator" have the same problem. They are django.views.decorators.gzip.gzip_page and django.views.decorators.http.conditional_page.

There might be others lurking out there...

[Mihai Damian]

@cache_page works for shure, just tested it last night

[Jacob]

This also applies to the new etag, last_modified, and condition decorators.

[Luke Plant]

(In [11586]) Fixed #6371 - several decorators don't work with bound methods.

This involved changing the way the internal function
decorator_from_middleware works slightly, breaking some code that relied on
the old behaviour. As a result, it is much simpler, but cache_page has been
made slightly more complex to cope with the change.