version/null: add major, minor, patch methods

Library/Homebrew/version/null.rb

@@ -37,6 +37,26 @@ class Version
     alias_method :requires_sse42?, :requires_nehalem_cpu?
     alias_method :requires_popcnt?, :requires_nehalem_cpu?
 
+    def major
+      NULL_TOKEN
+    end
+
+    def minor
+      NULL_TOKEN
+    end
+
+    def patch
+      NULL_TOKEN
+    end
+
+    def major_minor
+      self
+    end
+
+    def major_minor_patch
+      self
+    end
+
     def to_f
       Float::NAN
     end