Linker args order

Summary of my fight with libbz2

lbz2 isn't used directly by erocksdb but it's a transitive dependency that comes from rocksdb. Linker is a lazy guy so if you ask it to link lbz2 before rocksdb it will simply ignore lbz2.

Reference: http://stackoverflow.com/questions/11893996/why-does-the-order-of-l-option-in-gcc-matter