Invert the conditionals to make easier to read

Also improve some of the code conventions

Author: rafaelfranca

activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb

@@ -186,10 +186,10 @@ def column_exists?(table_name, column_name, type = nil, options = {})
       def create_table(table_name, options = {})
         td = create_table_definition table_name, options[:temporary], options[:options], options[:as]
 
-        unless options[:id] == false || options[:as]
-          pk = options.fetch(:primary_key) {
+        if options[:id] != false && !options[:as]
+          pk = options.fetch(:primary_key) do
             Base.get_primary_key table_name.to_s.singularize
-          }
+          end
 
           td.primary_key pk, options.fetch(:id, :primary_key), options
         end
@@ -201,7 +201,7 @@ def create_table(table_name, options = {})
         end
 
         result = execute schema_creation.accept td
-        td.indexes.each_pair { |c,o| add_index table_name, c, o } unless supports_indexes_in_create?
+        td.indexes.each_pair { |c, o| add_index(table_name, c, o) } unless supports_indexes_in_create?
         result
       end