* src/options.c,src/options.h: backport the addition of the "krb4_use_as_req"
    	and "krb4_convert_524" options from 2.2.x.  Note: requiring these to be
    	enabled by the option-parsing code disables afs5log's attempts to
    	perform the conversion itself, but since we've probably got krb524init
    	on the system, it shouldn't be received as a negative change.
    * src/pam_krb5.5.in,src/pam_krb5.8.in: backport docs for the newly-added
    	options.
    * src/tokens.c(tokens_obtain): if the module's configured to use neither a v4
    	AS-REQ nor a 524 server, don't bother with non-2b methods of setting
    	tokens.
    * src/v4.c(v4_get_creds): heed the v4_use_as_req and v4_use_524 option settings.
    * bump the version