Add missing profile functions to libkrb5 exports

profile_flush_to_buffer, profile_flush_to_file, profile_free_buffer,
profile_init_flags, and profile_init_vtable are all public profile
functions, but are inaccessible to libkrb5 applications on some
platforms because they were never added to the export list.  Add them
now.

(libprofile functions have never been part of the Windows DLL export
list, so do not change krb5_32.def at this time.)

ticket: 7930 (new)
target_version: 1.12.2
tags: pullup