ms-sys: bump version to 2.4.0 and fix install path

[roarde]

Don't know how it got installed correctly on RC2.2.2, but the package in the repo installs to /usr/local.

Attached patch builds it locally, but was checked directly on host, not in clean jail.

[Moises Henriquez]

Fix #20 : Accepted patch by roarde for ms-sys

→ <<cset 358627e517b7>>