tdb: consolidate tdb allocation code - re-use dead records at hash top.

When in tdb_store we re-use a dead record reactivated from the
target hash chain itself, we currently leave it in its place in
the chain. When we re-use a dead record from a different chain or
from the freelist instead, we insert it at the beginning of the
target chain.

This patch changes the behaviour to always newly store a
record at the beginning of the hash chain. This removes
a special case and hence simplifies the allocation code.
On the other hand side, it introduces two additioal tdb_ofs_write
calls for the in-chain-case.

Note the subtelty of the patch that by moving the case of the candidate
record's chain as new case "i=0" into the for loop, we also reverse the
order of the two steps in the for-loop body (non blocking freelist alloc
and searching for dead record in a chain) in order to keep the overall
order of execution identical.

Signed-off-by: Michael Adam <obnox@samba.org>
Reviewed-by: Volker Lendecke <vl@samba.org>
Reviewed-by: Jeremy Allison <jra@samba.org>

Autobuild-User(master): Michael Adam <obnox@samba.org>
Autobuild-Date(master): Wed Apr  9 10:37:08 CEST 2014 on sn-devel-104
s4-wbclient: Fix wbc_sids_to_xids to correctly indicate the length of the SID list

This uses the fact that we know the end of the string in p to avoid
needing a strlen() call.  Otherwise the winbindd validation that the
extra_data is terminated may fail, if the un-initiliased memory is not
zero.

Andrew Bartlett

Change-Id: I9b28068e4fbd3754c8d14724af93638d657810dd
Signed-off-by: Andrew Bartlett <abartlet@samba.org>
Reviewed-by: Volker Lendecke <vl@samba.org>

Autobuild-User(master): Volker Lendecke <vl@samba.org>
Autobuild-Date(master): Wed Apr  9 18:26:40 CEST 2014 on sn-devel-104