Fix incorrect private lib field in librabbitmq.pc
Fix incorrect private lib field in librabbitmq.pc

Fixes #599

Private lib entries are currently separated by semicolon.
Replace semicolon by space and add -l prefix to libs.

Signed-off-by: Andriy Gelman <9b800b50c068448b0612a5bdc33ac199b44926a7@gmail.com>

alanxz/rabbitmq-c,alanxz/rabbitmq-c,alanxz/rabbitmq-c