http.c: fix an invalid free()
http.c: fix an invalid free()

Remove a free() on the static buffer returned by sha1_file_name().

While we're at it, replace xmalloc() calls on the structs
http_(object|pack)_request with xcalloc() so that pointers in the
structs get initialized to NULL. That way, free()'s are safe - for
example, a free() on the url string member when aborting.

This fixes an invalid free().

Reported-by: Ævar Arnfjörð Bjarmason <0135fcc047f75af264c800977a73e353c6ba842d@gmail.com>
Helped-by: bc271c95f9edf76cb349228ea9d84d39540066ce@peff.net
Signed-off-by: Tay Ray Chuan <781f23e367a7ada1fde54f9860fdd95ca652794e@gmail.com>
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