* asn1buf.c (asn12krb5_buf): Initialize magic fields of structure.

	* asn1buf.c (asn12krb5_buf): Initialize magic fields of structure.
	(asn1buf_expand): If pre-allocating memory for future use, store
		proper end of buffer.

This was a big performance hit in asn.1 routines as every time it tried to
decode an octet, 200 bytes were allocated (for future use), but the
buffer structure pnly thought that one byte was allocated and the next
time through would try to allocate memory again.

git-svn-id: svn://anonsvn.mit.edu/krb5/trunk@8553 dc483132-0cff-0310-8789-dd5450dbe970