Fix bug 1525

This patch adds **kwargs in the LCMHelmConn methods that are not used.
The feature 10239 added the vca_id parameter for the LCM and N2VC
communication for Juju related execution environments. The current patch
will avoid having to add extra parameters that are not needed nor used
in the LCMHelmmConn.

Change-Id: I673a36c7c13891a53de1d7dc547f13c81616d373
Signed-off-by: David Garcia <david.garcia@canonical.com>