Use 'ssh' on servers explicitly

The current implementation does not work correcly on Windows as it
tried to use %SCP% on remove server as well which runs Unix system.
On servers always use 'ssh' explicitly.

Change-Id: I923a7da56fd2745e21ffac181b3dc356ee1128c7
Reviewed-by: Sergio Ahumada <sergio.ahumada@digia.com>