Do not require sudo/rootwrap to check for dnsmasq version

The dnsmasq version check does not need root privileges
to run as with low privs it works just fine. As a side
effect, the use of the rootwrapper was causing unit tests
to hung because the execute call in check_version was not
being stubbed out. Weirdly enough this wasn't caught in
a previous Gerrit run; there must be a passwordless sudo
lurking around somewhere in the Gerrit infrastructure.

Fixes bug #1178800

Change-Id: I4d0bd218768eec2439d3907587682ff35884a262