Strip apostrophe from email generated usernames.

lib/gitlab/ldap/user.rb

@@ -50,7 +50,9 @@ module Gitlab
           # we look for user by extracting part of their email
           if !user && email && ldap_conf['allow_username_or_email_login']
             uname = email.partition('@').first
-            user = model.find_by(username: uname)
+            # Strip apostrophes since they are disallowed as part of username
+            username = uname.gsub("'", "")
+            user = model.find_by(username: username)
           end
 
           user

lib/gitlab/oauth/user.rb

@@ -39,7 +39,9 @@ module Gitlab
             # So we use part of email as username for new user
             # For LDAP, username is already set to the user's
             # uid/userid/sAMAccountName.
-            user.username = email.match(/^[^@]*/)[0]
+            email_username = email.match(/^[^@]*/)[0]
+            # Strip apostrophes since they are disallowed as part of username
+            user.username = email_username.gsub("'", "")
           end
 
           user.save!