Accept buffered IO stream objects as fd in hdrFromFdno

[rajulkumar]

One of the tests for rcm-pa-tool failed with below error that previously worked with rpm-py-installer.

rcm_pa_tool/pa_chains/upload_rpm_to_repo.py:19: in call
    hdr = ts.hdrFromFdno(fdno)
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 

self = <rpmdyn._transaction.TransactionSet object at 0x7f02ffefc650>
fd = <_io.BufferedReader name='tests/test_data/pulp-test-package-0.3.1-1.fc11.x86_64.rpm'>

    def hdrFromFdno(self, fd):
>       assert isinstance(fd, int)
E       AssertionError

fd arg to hdrFromFdno might be a buffered IO stream object like the one returned by open() as mentioed above. As rpm.transaction.hdrFromFdno accepts the buffered IO object as fd, the same method here should accept the object as well.