fix typos of source comments at Member model

git-svn-id: http://svn.redmine.org/redmine/trunk@13074 e93f8b46-1217-0410-a6f0-8f06a7374b81

Author: marutosi

app/models/member.rb

@@ -89,7 +89,7 @@ def set_issue_category_nil
     end
   end
 
-  # Find or initilize a Member with an id, attributes, and for a Principal
+  # Find or initialize a Member with an id, attributes, and for a Principal
   def self.edit_membership(id, new_attributes, principal=nil)
     @membership = id.present? ? Member.find(id) : Member.new(:principal => principal)
     @membership.attributes = new_attributes