Update README.md

Added Ossec.
Tarsnap is not actually Open Source Software

The source code is available for the sole use of the tarsnap backup service,
proper. Full license text from COPYING as follows:

Unless specified otherwise in individual files or directories, the
contents of this package is covered by the following copyright, license,
and disclaimer:

Copyright 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013 Colin Percival
All rights reserved.

Redistribution and use in source and binary forms, without modification,
is permitted for the sole purpose of using the "tarsnap" backup service
provided by Colin Percival.

THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
SUCH DAMAGE.
Added a new section "Load Testing", that includes 2 tools, Gatling and
JMeter.
Added couchbase to list of key/value stores
Merge branch 'tarsnapIsNotOSS' of https://github.com/winny-/awesome-sysadmin
Merge branch 'master' of https://github.com/aaronky/awesome-sysadmin
Merge branch 'load-testing' of https://github.com/jvrplmlmn/awesome-sysadmin
Merge branch 'patch-1' of https://github.com/b-jazz/awesome-sysadmin