[patch] wrap the inner function of the condition decorator

[portante]

Like all the other inner functions in the ​django/views/decorators/http.py module, wrap the inner function so that it exposes it's wrapped function's attributes.

Ran the unit tests successfully on my Mac Book Pro (10.6.7, 2 cores, 4 GB), see attached unit test run output.

[patchhammer]

15840.patch.diff fails to apply cleanly on to trunk

[dmclain]

Sackcloth and ashes tour

[Jonas Obrist]

Patch doesn't apply clean on trunk.

[Zbigniew Siciarz]

Improved the patch so it applies cleanly to current trunk. Only the condition decorator needs testing, as the other two are implemented in terms of it.

[Łukasz Rekucki]

Verified.

[Jannis Leidel]

In [17470]:

Fixed #15840 -- Wrapped inner function of the condition decorator with functools.wraps to follow best practices. Thanks, zsiciarz.