sg3_utils: freestanding sg_pr2serr.c pr_s 25+26

In order to use the new JSON code in pr2serr.[hc]
in the lsscsi package, changes were made to
remove dependencies on the rest of the sg_lib
library.

https://github.com/doug-gilbert/sg3_utils/pull/25
and .../pull/26 applied with minor change. More
pull requests await the next revision.



git-svn-id: https://svn.bingwo.ca/repos/sg3_utils/trunk@974 6180dd3e-e324-4e3e-922d-17de1ae2f315