Remove extra white spaces.

activerecord/lib/active_record/associations.rb

@@ -33,7 +33,7 @@ def initialize(owner_class_name, reflection)
 
   class HasManyThroughAssociationPointlessSourceTypeError < ActiveRecordError #:nodoc:
     def initialize(owner_class_name, reflection, source_reflection)
-      super("Cannot have a has_many :through association '#{owner_class_name}##{reflection.name}' with a :source_type option if the '#{reflection.through_reflection.class_name}##{source_reflection.name}' is not polymorphic.  Try removing :source_type on your association.")
+      super("Cannot have a has_many :through association '#{owner_class_name}##{reflection.name}' with a :source_type option if the '#{reflection.through_reflection.class_name}##{source_reflection.name}' is not polymorphic. Try removing :source_type on your association.")
     end
   end
 
@@ -48,7 +48,7 @@ def initialize(reflection)
       through_reflection      = reflection.through_reflection
       source_reflection_names = reflection.source_reflection_names
       source_associations     = reflection.through_reflection.klass.reflect_on_all_associations.collect { |a| a.name.inspect }
-      super("Could not find the source association(s) #{source_reflection_names.collect{ |a| a.inspect }.to_sentence(:two_words_connector => ' or ', :last_word_connector => ', or ', :locale => :en)} in model #{through_reflection.klass}.  Try 'has_many #{reflection.name.inspect}, :through => #{through_reflection.name.inspect}, :source => <name>'.  Is it one of #{source_associations.to_sentence(:two_words_connector => ' or ', :last_word_connector => ', or ', :locale => :en)}?")
+      super("Could not find the source association(s) #{source_reflection_names.collect{ |a| a.inspect }.to_sentence(:two_words_connector => ' or ', :last_word_connector => ', or ', :locale => :en)} in model #{through_reflection.klass}. Try 'has_many #{reflection.name.inspect}, :through => #{through_reflection.name.inspect}, :source => <name>'. Is it one of #{source_associations.to_sentence(:two_words_connector => ' or ', :last_word_connector => ', or ', :locale => :en)}?")
     end
   end
 
@@ -96,7 +96,7 @@ def initialize(reflection)
 
   class ReadOnlyAssociation < ActiveRecordError #:nodoc:
     def initialize(reflection)
-      super("Can not add to a has_many :through association.  Try adding to #{reflection.through_reflection.name.inspect}.")
+      super("Can not add to a has_many :through association. Try adding to #{reflection.through_reflection.name.inspect}.")
     end
   end