Cast host value to string prior to empty? check.

Force string type prior to empty? check to prevent errors if
host ip value is nil. Add coverage for proper handling of nil
value.

plugins/communicators/winrm/helper.rb

@@ -33,7 +33,7 @@ module VagrantPlugins
         return addr if addr
 
         ssh_info = machine.ssh_info
-        raise Errors::WinRMNotReady if !ssh_info || ssh_info[:host].empty?
+        raise Errors::WinRMNotReady if !ssh_info || ssh_info[:host].to_s.empty?
         return ssh_info[:host]
       end
 

test/unit/plugins/communicators/winrm/helper_test.rb

@@ -42,6 +42,12 @@ describe VagrantPlugins::CommunicatorWinRM::Helper do
       expect { subject.winrm_address(machine) }.
         to raise_error(VagrantPlugins::CommunicatorWinRM::Errors::WinRMNotReady)
     end
+
+    it "raise a WinRMNotReady exception if it detects an unset host ip" do
+      machine.stub(ssh_info: { host: nil })
+      expect { subject.winrm_address(machine) }.
+        to raise_error(VagrantPlugins::CommunicatorWinRM::Errors::WinRMNotReady)
+    end
   end
 
   describe ".winrm_info" do