fix autotools when dependency-tracking is disabled
fix autotools when dependency-tracking is disabled

The --enable-dependency-tracking flag causes the librabbitmq/gen
directory to be created automagically, when it should be explicitly
created.

Also the librabbitmq/gen should only be included if we're regenerating
the amqp_framing.h/.c files

tempbottle/rabbitmq-c,sakishum/rabbitmq-c,kilinrax/rabbitmq-c,Haster2004/rabbitmq-c,soindy/rabbitmq-c,sakishum/rabbitmq-c,chenwenbin928/rabbitmq-c,chenwenbin928/rabbitmq-c,hjzljp/rabbitmq-c,jqk6/rabbitmq-c,Haster2004/rabbitmq-c,sakishum/rabbitmq-c,jasonmsoft/rabbitmq-c,hjzljp/rabbitmq-c,tempbottle/rabbitmq-c,soindy/rabbitmq-c,jqk6/rabbitmq-c,hjzljp/rabbitmq-c,jqk6/rabbitmq-c,jasonmsoft/rabbitmq-c,Haster2004/rabbitmq-c,jasonmsoft/rabbitmq-c,chenwenbin928/rabbitmq-c,tempbottle/rabbitmq-c,tempbottle/rabbitmq-c,kilinrax/rabbitmq-c,alanxz/rabbitmq-c,hjzljp/rabbitmq-c,kilinrax/rabbitmq-c,jqk6/rabbitmq-c,jasonmsoft/rabbitmq-c,alanxz/rabbitmq-c,soindy/rabbitmq-c,alanxz/rabbitmq-c