[krbdev.mit.edu #7765] Some ccache functions not exported

[Greg Hudson via RT]

r20743 (which went into 1.7) added several ccache APIs without adding to 
them either the Unix or Windows export lists:

  krb5_cc_last_change_time
  krb5_cc_lock
  krb5_cc_move
  krb5_cc_unlock
  krb5_cccol_last_change_time
  krb5_cccol_lock
  krb5_cccol_unlock

krb5_cc_move has since been added to the export lists (by commit 
ad5aa12f13aad7ec4cafcffeec4f2e84e56c9c78 which went in 1.11), but the 
others have not.  Although the other functions are probably unused (or 
we would have received bug reports), they are documented and prototyped 
in krb5.h, and we have learned of plans to possibly use 
krb5_cc_last_change_time.