new copy_data_contents variant that null-terminates

new copy_data_contents variant that null-terminates

pull up r21893 from trunk

 ------------------------------------------------------------------------
 r21893 | raeburn | 2009-02-05 13:42:10 -0500 (Thu, 05 Feb 2009) | 4 lines
 Changed paths:
    M /trunk/src/include/k5-int.h
    M /trunk/src/lib/kdb/kdb_cpw.c
    M /trunk/src/lib/krb5/krb/bld_pr_ext.c
    M /trunk/src/lib/krb5/krb/copy_data.c
    M /trunk/src/lib/krb5/krb/copy_princ.c
    M /trunk/src/lib/krb5/libkrb5.exports

 Create and use (in several places) a variant of
 krb5int_copy_data_contents that adds a trailing '\0' so the result can
 be used as a C string.

ticket: 6467
version_fixed: 1.7
tags: pullup
target_version: 1.7

git-svn-id: svn://anonsvn.mit.edu/krb5/branches/krb5-1-7@22240 dc483132-0cff-0310-8789-dd5450dbe970