vcs-svn: Fix some printf format compiler warnings

vcs-svn: Fix some printf format compiler warnings

In particular, on systems that define uint32_t as an unsigned long,
gcc complains as follows:

      CC vcs-svn/fast_export.o
  vcs-svn/fast_export.c: In function `fast_export_modify':
  vcs-svn/fast_export.c:28: warning: unsigned int format, uint32_t arg (arg 2)
  vcs-svn/fast_export.c:28: warning: int format, uint32_t arg (arg 3)
  vcs-svn/fast_export.c: In function `fast_export_commit':
  vcs-svn/fast_export.c:42: warning: int format, uint32_t arg (arg 5)
  vcs-svn/fast_export.c:62: warning: int format, uint32_t arg (arg 2)
  vcs-svn/fast_export.c: In function `fast_export_blob':
  vcs-svn/fast_export.c:72: warning: int format, uint32_t arg (arg 2)
  vcs-svn/fast_export.c:72: warning: int format, uint32_t arg (arg 3)
      CC vcs-svn/svndump.o
  vcs-svn/svndump.c: In function `svndump_read':
  vcs-svn/svndump.c:260: warning: int format, uint32_t arg (arg 3)

In order to suppress the warnings we use the C99 format specifier
macros PRIo32 and PRIu32 from <inttypes.h>.

Signed-off-by: Ramsay Jones <ramsay@ramsay1.demon.co.uk>
Acked-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>