kproplog currently assumes that an iprop log is full once it has
circled--which is true right now but will need to change for
hierarchical slaves.  Avoid this assumption by using the correct
index modulus in print_update whether or not the log is full.

Based on a patch from Richard Basch <basch@alum.mit.edu>.

[ghudson@mit.edu: simplify slightly]

If the master iprop log is reinitialized to serial number 0, slaves
will need to take a full dump--but after that happens, we need to know
whether the slave has taken that full dump, we we don't offering full
dumps indefinitely.

So, record a timestamp in kdb_last_time when we reinitialize the log
header, and compare the slave timestamp to kdb_last_time whenever it
has the current serial number, even if it's 0.  Test this by
performing a propagation with sno 0 in t_iprop.py and detecting
whether kpropd gets a second UPDATE_FULL_RESYNC_NEEDED response from
kadmind.

ticket: 7550 (new)

Mostly this gets rid of the trailing space on line 2 after
bb76891f5386526bdf91bc790c614fc9296cb5fa.

Since there is no overlap between the clpreauth and kdcpreauth
interface declarations, there's no particular reason to combine them
into one header.  For backward compatibility and convenience, leave
behind a preauth_plugin.h which includes both.

The old man pages are gone, so we can't install them anymore.
Also clean up install and install-unix targets that were installing
the old man pages by hand.

We generate man pages from RST sources now; they are checked into
the tree in src/man/.

The gen-manpages directory is no longer needed.

Catch SIGUSR1 in iprop-mode kpropd so that we can use it to interrupt
sleeps and make kpropd do an iprop request immediately.

In k5test.py, add prod_kpropd and read_from_kpropd methods to allow
test scripts to send a SIGUSR1 to kpropd and to read its stdout/stderr
output; also allow the test script to specify additional arguments
when starting kpropd.

In t_iprop.py, start kpropd with -d and, instead of sleeping, read
kpropd output until we see an indication that kpropd is in sync with
the master.  To avoid delays, prod kpropd before waiting for sync and
after a completed full prop.

Fix kpropd -S -t to actually exit after processing one connection (it
was breaking out of the switch statement, not the while loop).  Use
the -t when invoking kpropd from the dejagnu test framework;
previously it was unnecessary because kpropd -S -d exited after one
connection.  Clear up some confusion in the kprop.exp comments about
whether kpropd is expected to exit.