Fixing format_ssh_command

format_ssh_command failed setting the Identity file
causing an error like no such file or directory.

Change-Id: Ic401993a4ebbcfa99335673e70fc0ae6d191b279
Bug-Url: https://bugzilla.redhat.com/904719
Signed-off-by: Sandro Bonazzola <sbonazzo@redhat.com>