Fix KVM page to display the KVM session

Launching a KVM session on the KVM page stopped working. The websocket
connection request began returning connection failure error
codes. This change fixes the asynchronous connection request to allow
it to succeed, and in turn display the KVM session.

Tested:
Connect to BMC using Chrome (FC31), selected Control->KVM sidebar.
Witnessed the KVM session started, and interacted with the SUT while
it was in UEFI.

Connect to BMC using Chrome (Windows 10), selected Control->KVM
sidebar. Witnessed the KVM session started, and interacted with the
SUT while it was in UEFI. Events performed from the Windows browser were
duplicated in the FC31 browser.

Change-Id: Ib3721990dce2e2ba71235371d903fbf508075077
Signed-off-by: Johnathan Mantey <johnathanx.mantey@intel.com>