Maint: Don't test for extended signals on Windows
The signals HUP, USR1, and USR2 are not supported on Windows. The
Puppet::Daemon code already skipped trapping these on Windows,
but the spec test was expecting them to be trapped. This commit
just updates the spec test to match the existing daemon code.
Reviewed-by: Jacob Helwig <jacob@puppetlabs.com>
(cherry picked from commit 8d56355981961fd1c4a358992930bbb80325fea7)