rdfind: upgrade 1.5.0 -> 1.6.0

0001-configure-Fix-check-for-AC_CHECK_LIB.patch
0001-include-standard-headers-limits-and-cstdint.patch
0001-configure.ac-fix-C-11-support-check.patch
removed since they're included in 1.6.0

Changelog:
 add sha512 support

Signed-off-by: Wang Mingyu <wangmy@fujitsu.com>
Signed-off-by: Khem Raj <raj.khem@gmail.com>