Use @wraps for withLockedLU
Use @wraps for withLockedLU

This change enables tools like 'nose2' to execute only one single test
method, which is a great help when debugging. Plus using wraps is good
style for a wrapper.

Signed-off-by: Aaron Karper <99cc1031546340b2b8ced5fe338b5890677a56ca@google.com>
Signed-off-by: Michele Tartara <05f7077a2c6cbbdc4af4ba42e3ef89a0df846179@google.com>
Reviewed-by: Michele Tartara <05f7077a2c6cbbdc4af4ba42e3ef89a0df846179@google.com>

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