hdf5_ep

[svn-r22601] Purpose: Fix HDFFV-5853

Description:
When jumping out from between H5_BEGIN_TAG and H5_END_TAG macros using
HGOTO_ERROR or HGOTO_DONE, the previous metadata tag is not reset on the dxpl.
This could cause problems when, for example, calling H5Ocopy within an
H5Literate callback.

Added new HGOTO_ERROR_TAG and HGOTO_DONE_TAG macros which must be used in place
of the above between H5_BEGIN_TAG and H5_END_TAG.

Tested:
jam, koala, ostrich (h5committest), durandal