[vSphere] Support passing of a distributed switch for each interface.
Update excon dependency to version ~>0.27.0
Merge pull request #2223 from sferik/update_excon_dependency

Update excon dependency to version ~>0.27.0
Merge pull request #2185 from grimme-atix-de/interface_dswitch

[vSphere] Support passing of a distributed switch for each interface.
Auto-merge remote-tracking branch 'upstream/master'