sha1_file.c: Fix size_t related printf format warnings
The old way of fixing warnings did not succeed on MinGW. MinGW
does not support C99 printf format strings for size_t [1]. But
gcc on MinGW issues warnings if C99 printf format is not used.
Hence, the old stragegy to avoid warnings fails.
[1] http://www.mingw.org/MinGWiki/index.php/C99
This commits passes arguments of type size_t through a tiny
helper functions that casts to the type expected by the format
string.
Signed-off-by: Steffen Prohaska <prohaska@zib.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>