Clean dangling image fragments in filesystem store

Fixes bug LP 1104924

Previously when a PUT or POST of image content was terminated
prematurely by the client, the partially saved image file was
left behind in the data directory.

Change-Id: Id601816735e4138cd7623dad4d90be67448292c8
Wait in TestBinGlance.test_update_copying_from until image is active

Test randomly fails on slow machines, the updated image is still
in 'Status: saving' while 'Status: active' is expected. So loop around
the "glance show" command until the image leaves the 'saving' state
(bug 1107768).

Change-Id: I908069b35079dcc8ccd25acb3ebc74fe43f9d524
Merge "Clean dangling image fragments in filesystem store" into stable/folsom
Merge "Wait in TestBinGlance.test_update_copying_from until image is active" into stable/folsom