Add RunLocalHooks decorator
Add RunLocalHooks decorator

Add the RunLocalHooks decorator, that allows the execution of hooks
locally. Also, add a RunLocalHooks method to HooksRunner, to adapt the
signature of HooksRunner.RunHooks to the one expected by HooksMaster,
and also to check that the hooks are being executed locally.

Reviewed-by: Michael Hanselmann <68b67885ff74281219b4a4be33cc20fd45078d7c@google.com>
Signed-off-by: Andrea Spadaccini <92d490849ac1b40cd8e8878e4d94603bebdb089f@google.com>

leshchevds/ganeti,apyrgio/snf-ganeti,yiannist/ganeti,dimara/ganeti,dimara/ganeti,onponomarev/ganeti,grnet/snf-ganeti,andir/ganeti,apyrgio/ganeti,ganeti/ganeti,andir/ganeti,ganeti/ganeti,mbakke/ganeti,ganeti/ganeti,bitemyapp/ganeti,apyrgio/snf-ganeti,mbakke/ganeti,apyrgio/ganeti,leshchevds/ganeti,mbakke/ganeti,onponomarev/ganeti,ganeti-github-testing/ganeti-test-1,leshchevds/ganeti,yiannist/ganeti,ganeti-github-testing/ganeti-test-1,bitemyapp/ganeti,grnet/snf-ganeti,yiannist/ganeti,andir/ganeti