hdf5_msb

Delete superfluous casts.  Remove superfluous backslashes and
statement-ify, changing

    HGOTO_ERROR(..., \
             )

to

    HGOTO_ERROR(...,
             );

Remove blank lines between if-clause and HGOTO_ERROR.  Add some curly
braces to if-statements where that clarifies things.

NFCI.