[module] pass ssr as is

This prevents defaulting ssr to false when undefined

lib/module.js

@@ -55,7 +55,7 @@ class Module {
     // Add to nuxt plugins
     this.options.plugins.push({
       src: '~/.nuxt/' + dst,
-      ssr: Boolean(template.ssr),
+      ssr: template.ssr,
       injectAs: template.injectAs
     })
   }