Get rid of the global krb5 context used by the GSSAPI Kerberos mechanism. I

Get rid of the global krb5 context used by the GSSAPI Kerberos mechanism.  I
*think* I've gotten all the places where a ccache or keytab name that's been
stored gets applied to whichever context needs it.

* gssapi_krb5.c (kg_sync_ccache_name): Add context argument instead of calling
kg_get_context.
(kg_get_ccache_name): Use a locally created krb5 context instead of calling
kg_get_context.
(kg_get_context): Deleted.
* acquire_cred.c (acquire_init_cred): Pass current context.
(krb5_gss_acquire_cred): Use a locally created krb5 context instead of calling
kg_get_context.
* add_cred.c (krb5_gss_add_cred): Call kg_sync_ccache_name.
* init_sec_context.c (krb5_gss_init_sec_context): Likewise.
* gssapiP_krb5.h (kg_sync_ccache_name): Update prototype.
(kg_get_context): Delete declaration.

git-svn-id: svn://anonsvn.mit.edu/krb5/trunk@16597 dc483132-0cff-0310-8789-dd5450dbe970