Start logging unexpected responses in kaltura

refs LS-3015
flag=none

Change-Id: I5ce3a0934b30ddc3a07058c68bcebe718435d260
Reviewed-on: https://gerrit.instructure.com/c/canvas-lms/+/286836
Tested-by: Service Cloud Jenkins <svc.cloudjenkins@instructure.com>
Reviewed-by: Jackson Howe <jackson.howe@instructure.com>
QA-Review: Jackson Howe <jackson.howe@instructure.com>
Product-Review: Luis Oliveira <luis.oliveira@instructure.com>

gems/canvas_kaltura/lib/canvas_kaltura/kaltura_client_v3.rb

@@ -369,7 +369,9 @@ module CanvasKaltura
         requestParams += "&#{URI.escape(key.to_s)}=#{URI.escape(value.to_s)}"
       end
       response = sendRequest(Net::HTTP::Get.new("#{@endpoint}/?#{requestParams}"))
-      Nokogiri::XML(response.body).css("result").first
+      result = Nokogiri::XML(response.body).css("result").first
+      Canvas::Errors.capture("Unexpected kaltura_client response", response, :info) if result.nil?
+      result
     end
 
     # FIXME: SSL verifification should not be turned off, but since we're just