http-backend: Let gcc check the format of more printf-type functions.
http-backend: Let gcc check the format of more printf-type functions.

We already have these checks in many printf-type functions that have
prototypes which are in header files.  Add these same checks to
static functions in http-backend.c

Signed-off-by: Tarmigan Casebolt <54dc374c49e31b8dd9ae6132f5d27147d81f0d85@gmail.com>
Acked-by: Shawn O. Pearce <f01032651c12a22b2103346ba96b3b6b231f9d3c@spearce.org>
Signed-off-by: Junio C Hamano <a6723cc3f76163bf7adb636a73ac3b0ceb3e6b9b@pobox.com>

destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git