pull up r19396 from trunk

pull up r19396 from trunk

 r19396@cathode-dark-space:  tlyu | 2007-04-03 17:27:25 -0400
 ticket: new
 subject: MITKRB5-SA-2007-001: telnetd allows login as arbitrary user
 tags: pullup
 target_version: 1.6.1

 Fix MITKRB5-SA-2007-001:

 	* src/appl/telnet/telnetd/sys_term.c (start_login): Add "--"
 	argument preceding username, in addition to the original patch.
 	Explicitly check for leading hyphen in username.

 	* src/appl/telnet/telnetd/state.c (envvarok): Check for leading
 	hyphen in environment variables.  On advice from Shawn Emery, not
 	using strchr() as in the original patch.

ticket: 5512
version_fixed: 1.5.3

git-svn-id: svn://anonsvn.mit.edu/krb5/branches/krb5-1-5@19403 dc483132-0cff-0310-8789-dd5450dbe970