Cleaned up FLDPLUS handling in m_getfld(). As part of this,

Cleaned up FLDPLUS handling in m_getfld().  As part of this,
removed the backing up of the read pointer in the "something
went wrong" portion of the FLD handling.  It had been moved
back two positions.  The first is no longer necessary
because a Getc() was replace by a Peek(), and the second
caused the extra blank line noted in the old comments.
Updated the expected output in test/bad-input/test-header to
correspond.