Removed temporary certificate to follow recommendation not store secrets in code. (#741)

Author: abodalevsky

Examples/CodePushDemoApp/windows/CodePushDemoApp/CodePushDemoApp.csproj

@@ -183,7 +183,6 @@
     <AppxManifest Include="Package.appxmanifest">
       <SubType>Designer</SubType>
     </AppxManifest>
-    <None Include="CodePushDemoApp_TemporaryKey.pfx" />
   </ItemGroup>
   <ItemGroup>
     <Content Include="Properties\Default.rd.xml" />