Handle empty frontmatter without logging an exception

middleman-core/lib/middleman-core/core_extensions/front_matter.rb

@@ -89,12 +89,13 @@ module Middleman::CoreExtensions
           content = content.sub(yaml_regex, "")
 
           begin
-            data = YAML.load($1).symbolize_keys
+            data = YAML.load($1)
+            return false unless data
+            data.symbolize_keys
           rescue *YAML_ERRORS => e
             logger.error "YAML Exception: #{e.message}"
             return false
           end
-
         else
           return false
         end