tools: remove unused sysconfig variable XENSTORED_ROOTDIR

The sysconfig variable XENSTORED_ROOTDIR is not used anymore.
It used to point to a directory with tdb files, which is now a tmpfs.

In case the database is not in tmpfs, like on sysv and BSD systems,
xenstored will truncate existing database files during start.

Fixes: 2ef6ace428 ("tools: don't remove tdb data base file before starting xenstored")
Signed-off-by: Olaf Hering <olaf@aepfle.de>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Wei Liu <wl@xen.org>

CHANGELOG.md

@@ -6,6 +6,10 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 
 ## [unstable UNRELEASED](https://xenbits.xen.org/gitweb/?p=xen.git;a=shortlog;h=staging) - TBD
 
+### Removed
+ - XENSTORED_ROOTDIR environment variable from configuartion files and
+   initscripts, due to being unused.
+
 ## [4.15.0 UNRELEASED](https://xenbits.xen.org/gitweb/?p=xen.git;a=shortlog;h=RELEASE-4.15.0) - TBD
 
 ### Added / support upgraded