- Copy stable/10 (r259064) to releng/10.0 as part of the
10.0-RELEASE cycle.
- Update __FreeBSD_version [1]
- Set branch name to -RC1

[1] 10.0-CURRENT __FreeBSD_version value ended at '55', so
start releng/10.0 at '100' so the branch is started with
a value ending in zero.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Don't use sys/nfs/rpcv2.h - it is part of the old kernel RPC implementation
and will be removed.

Fix some bugs and general brain damage in mounttab:
- Declare mtabhead as an extern in mounttab.h and define it only in
mounttab.c.
- Remove shared global `verbose' and instead pass it as a parameter.
- Remove the `mtabp' argument to read_mtab(). It served no purpose
whatsoever, although read_mtab() did use it as a temporary local
variable.
- Don't check for impossible conditions when parsing mounttab, and
do detect zero-length fields.
- Correctly test for strtoul() failures - just testing ERANGE is wrong.
- Include a field name in syslog errors, and avoid passing NULL to
a syslog %s field.
- Don't test if arrays are NULL.
- If there are duplicates when writing out mounttab, keep the last
entry instead of the first, as it will have a later timestamp.
- Fix a few formatting issues.

Update rpc.umntall and umount to match the mounttab interface changes.

Add rpc.umntall utility, to be used by startup and shutdown scripts
to replace (broken) umntall signal code previously in mountd.

Submitted by: Martin Blapp <mb@imp.ch>