CP-9401: Use config file for executables in libexec

Stop using Fhs for libexecdir and make all the executables there configurable
options in the config file. The libexecdir is now on the search-path in the
config file.

Signed-off-by: Si Beaumont <simon.beaumont@citrix.com>
CP-9401: Remove unused OEM patch stream handler

Signed-off-by: Si Beaumont <simon.beaumont@citrix.com>
CP-9401: Don't use Fhs for xha directory (+ make it configurable)

Signed-off-by: Si Beaumont <simon.beaumont@citrix.com>
CP-9401: Don't use Fhs for hooks directory (+ make it configurable)

Signed-off-by: Si Beaumont <simon.beaumont@citrix.com>
CP-9401: Don't use Fhs for plugin directory (+ make it configurable)

Signed-off-by: Si Beaumont <simon.beaumont@citrix.com>
CP-9401: Don't use Fhs for gpg directory (+ make it configurable)

Signed-off-by: Si Beaumont <simon.beaumont@citrix.com>
CP-9401: Don't use Fhs.etcdir, use /etc/xensource

Signed-off-by: Si Beaumont <simon.beaumont@citrix.com>
CP-9401: Don't use Fhs.bindir

Make the paths to the binaries configurable and add the directory to the search
path.

Signed-off-by: Si Beaumont <simon.beaumont@citrix.com>
CP-9401: Don't use Fhs for web directory (+ make it configurable)

Signed-off-by: Si Beaumont <simon.beaumont@citrix.com>
CP-9401: Don't use Fhs for tools SR path (+ make it configurable)

Signed-off-by: Si Beaumont <simon.beaumont@citrix.com>
CP-9401: Don't use Fhs for post-install scripts (+ make it configurable)

Signed-off-by: Si Beaumont <simon.beaumont@citrix.com>
CP-9401: Correctly check provision scripts are whitelisted

Using the dirname instead of substring comparison allows us to not have to care
whether we have a '/' or not at the end of our (configurable) path but still
checks that they are actually in the directory that we allow (and not in
another directory that might start with the same string).

Signed-off-by: Si Beaumont <simon.beaumont@citrix.com>
CP-9401: Don't use Fhs for SM directory (+ make it configurable)

Signed-off-by: Si Beaumont <simon.beaumont@citrix.com>
CP-9401: Remove (now-)unused Fhs module

Signed-off-by: Si Beaumont <simon.beaumont@citrix.com>