Previously these would return the binary data, so since this fix is a

behavior change, blocking backport.

Blocked revisions 72605 via svnmerge

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  r72605 | r.david.murray | 2009-05-13 13:14:11 -0400 (Wed, 13 May 2009) | 3 lines

  Issue #4050: inspect.findsource/getsource now raise an IOError if the 'source'
  file is a binary.  Patch by Brodie Rao, test by Daniel Diniz.
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