May need to fix a test for bam-reader with `:chr` argument

[ayamada]

(came from #60 (comment) )

I add test for bam-reader with :chr argument in #60, but I found peculiar results in

cljam/test/cljam/t_bam.clj

Line 84 in ff91c66

(deftest bamreader-with-index

.
Possibly I wrong something, but I didn't know this reason.

[alumi]

Solved. Thanks!