HPCC-12029 Optimize crc_file, updated to fix Centos 5.7 and OSX build errors

Replaced new swap_bytes() routine with existing _REV4() from jmisc.hpp

Signed-off-by: Mark Kelly <mark.kelly@lexisnexis.com>
Merge pull request #6369 from mckellyln/crc

HPCC-12029 Optimize crc_file, updated to fix Centos 5.7 and OSX build er...

Reviewed-By: Richard Chapman <rchapman@hpccsystems.com>