Pull up r25591, r25604 from trunk

Pull up r25591, r25604 from trunk

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 r25604 | ghudson | 2011-12-27 01:39:07 -0500 (Tue, 27 Dec 2011) | 4 lines

 ticket: 6936

 Fix an unlikely memory leak in r25591
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 r25591 | ghudson | 2011-12-16 18:19:01 -0500 (Fri, 16 Dec 2011) | 14 lines

 ticket: 6936
 target_version: 1.10
 tags: pullup

 Do mech fallback for first SPNEGO context token

 When producing the first SPNEGO security context token, if the first
 mechanism's init_sec_context fails, fall back to a later mechanism.

 This fixes a regression in 1.10 for SPNEGO initiators using non-krb5
 credentials.  The identity selection work causes errors to be deferred
 from krb5's acquire_cred in some cases, which means SPNEGO doesn't see
 an error until it tries the krb5 init_sec_context.

ticket: 6936
version_fixed: 1.10
status: resolved

git-svn-id: svn://anonsvn.mit.edu/krb5/branches/krb5-1-10@25628 dc483132-0cff-0310-8789-dd5450dbe970