afs: Throttle byte-range locks warnings per-file

Currently, the warning messages about byte-range locks are throttled
only according to what the last PID of the locking process was. So, if
that same process performs a bunch of byte-range locks a bunch of
times, we log this warning message at most once every 2 minutes.

However, if we have even just one other process also performing
byte-range locks, the throttling can become pretty useless as
lastWarnPid ping-pongs back and forth between the two different PIDs.
This can happen if multiple unrelated byte-range-lock-using pieces of
software just happen to be running on the same machine, or if a piece
of software uses byte-range locks after forking into separate
processes.

To avoid flooding the log in situations like this, keep track of the
last warn time in the relevant vcache, so we don't get frequent
warnings for byte-range lock requests on the same file.

Change-Id: I446cf6a438a75aa741c5543b93f74f4184ee6508
Reviewed-on: http://gerrit.openafs.org/10796
Reviewed-by: D Brashear <shadow@your-file-system.com>
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Only include <sys/timeb.h> for Windows

This file is deprecated on FreeBSD, and appears to only be used
by OpenAFS on windows.

Change-Id: If10816f26da91855d10826d53501e5b9974cd292
Satisfy clang's aggressive strlcpy warnings

Passing something related to the length of the source as the
length argument to strlcpy triggers a warning, which is converted
to an error with --enable-checking (on FreeBSD 10.0).  The current
code is safe, since it is using the same expression that was used
to allocate the destination buffer, but switch to using a separate
variable to hold the length and use that variable for both allocation
and copying, to appease the compiler.
pioctl.c: removed unused variable

The 'rval' variable is only actually used in the LINUX20 case;
in all other places where it is assigned a value, that value
ends up in 'errcode' (if non-zero).  This also has the
side effect of eliminating the use of the uninitialized variable
'errcode' when rval was zero.

Found by clang on FreeBSD 10.0.
pointers are not castable to unsigned int

When printing a pointer's value for debugging purposes, use the
dedicated printf format specifier for pointers instead of assuming
that unsigned int ('x') is good enough.

Found by clang on FreeBSD 10.0.
Switch the dummy 'data' for mount(2)

The mount(2) API takes a void*, but 'rn' is const char*, which
is const-incorrect.  Our vfs_cmount implementation ignores the 'data'
parameter, but upstream's kernel mount(2) implementation did
have a NULL check until r158611 (in the 6.1 or 7.0 timeframe),
so leave that comment for now.

Arguably we should be using nmount(2) instead of mount(2) anyway,
but leave that for a separate patch.
fstrace: only declare 'rval' when it is used

... to avoid compiler warnings about unused variables.

Found by clang on FreeBSD 10.0.
aklog: those pesky assignments in conditionals

This one should actually be an assignment, and the compiler warning
for having two sets of parentheses is helpful.

Found by clang on FreeBSD 10.0.