CP-9401: Don't use Fhs.etcdir; instead use configurable paths

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

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

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

Conflicts:
	ocaml/xapi/xapi_globs.ml
	scripts/xapi.conf
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>

Conflicts:
	scripts/xapi.conf
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>
CP-9401: Remove unused option in globs

Signed-off-by: Si Beaumont <simon.beaumont@citrix.com>
CP-9401: Remove default hardcoded path in genptoken

This now generates the token in the current working directory rather than
putting it in an arbitrary hardcoded place. This can be overridden still (using
-o) which is done by the init script to ensure it ends up where it needs to be.

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