Relevant BUGIDs: #2009766

Relevant BUGIDs: #2009766

Purpose of commit: bugfix

Commit summary:
---------------
2008-07-11  Tomas Mraz <t8m@centrum.cz>

        * modules/pam_unix/pam_unix_acct.c (_unix_run_verify_binary): Do
        not close the pipe descriptor in borderline case (#2009766)
        * modules/pam_unix/pam_unix_passwd.c (_unix_run_update_binary):
        Likewise.
        * modules/pam_unix/support.c (_unix_run_helper_binary): Likewise.
        * modules/pam_unix/support.h: Define upper limit of fds we will
        attempt to close.