Minimize race conditions in t_iprop.py

Augment kpropd's debugging output so we can see the starting and
ending serial numbers of a sync, and check them in t_iprop.py's
wait_for_prop to make sure we're observing the correct sync each time.
Try to make sure we only send SIGUSR1 when kpropd is actually
sleeping, by waiting for it to print its pre-sleep message to stderr
after a full dump and after each sync.  This isn't perfect, as there
is a short window between printing to stderr and actually sleeping,
but we can't do any better until kpropd has a more reliable mechanism
for triggering immediate updates.
Assume <stdint.h> and fixed-width types

Make unconditional use of <stdint.h> and fixed-width types such as
uint32_t.  k5-plugin.h doesn't use any special integer types, so
remove the conditional include block there.  Nothing uses
INT64_FMT/UINT64_FMT, so leave those out of k5-platform.h for now.
Get rid of builtin AES uitypes.h

Remove uitypes.h and just include stdint.h; all we need from it is
uint{8,16,32}_t.
Stop generating gssapi_krb5.h

We started generating gssapi_krb5.h from gssapi_krb5.hin when we
needed to use a 64-bit type for lucid contexts.  Since we can now
assume a standard name for 64-bit types, we can stop generating the
header.
Eliminate internal fixed-width type wrappers

Directly use stdint.h names for integer types in preference to the
various internal names we have made up for them.
In kdb5_util dump, only lock DB for iprop dumps

Revert #7384, as there are no longer policy refcounts.  For iprop
dumps we want to make sure that the reported serial number matches the
DB state (although we could perhaps relax that requirement with enough
analysis), but for non-iprop dumps we don't need any transactional
guarantees.

Also use the correct constant name for the locking mode (the numeric
value is the same, fortunately), and only unlock the database if we
successfully locked it.

ticket: 7869 (new)
Fix two omissions in stdint.h changes

Since we no longer prefix an "#include <stdint.h>" in the gssapi.h
preamble at build time, include it in gssapi.hin.

Update util/gss/kernel-lib/Makefile.in to account for gssapi_krb5.h
being in the source tree.
Missing type refs in docs due to stdint.h changes

References to krb5_int16.rst and krb5_ui_2.rst were missing, but
recently began causing sphinx-build errors because Doxygen started
generating them after the stdint.h changes.