hdf5_der

[svn-r22016] Purpose:

    - Switch avoid_truncate from bool to enum

    - Enable 'EOA' message with latest format.

Description:

    Switched the 'avoid truncate' property from a bool
    (on/off) to an enum with the following states (for now):

        H5F_AVOID_TRUNCATE_OFF : file will always be
                                 truncated at file close

        H5F_AVOID_TRUNCATE_EXTEND: file will only be
                                   truncated on file close
                                   if that truncation
                                   results in a smaller
                                   file.

        H5F_AVOID_TRUNCATE_ALL: file will never be truncated
                                on file close.

    These may be renamed after RFC discussion ...

    This also resulted in a change in the API controlling
    the property, as well as the internal querying function.

    Also, using the latest format in a fapl when creating a
    file will now also trigger writing of an 'EOA' message
    and usage of avoid truncate feature. The default setting
    in this case is H5F_AVOID_TRUNCATE_EXTEND, as this will
    still allow files to reduce in size when space can be
    reclaimed.

    The above required some changes to expected test cases
    since the file format when the latest format is used now
    includes an 'EOA' message. A handful of the h5mkgrp test
    files had their locations updated, and the cache_tagging
    test was updated to account for superblock extension in
    the latest case.

    The change to an 'enum' required an update to the 'EOA'
    message, since there is no longer a one-to-one
    correspondence between the avoid truncate property
    setting and whether or not to store an EOA. As such, the
    avoid truncate property setting has been added into the
    EOA message, and a new EOA message struct created,
    H5O_eoa_t, to house it along with the EOA value.
    (message previously consisted of just the EOA value).

    The above change was propogated as needed, including
    changes made to the h5extend tool in order to account
    for the changes needed in acquiring the EOA value from
    the message stored in the superblock extension.

    Finally, the test file trunc_detect was renamed
    'truncation' since it does more than just test
    truncation detection. It was also refactored to account
    for the enumerated setting, and divided into three
    distinct parts: testing of setting the avoid truncate
    property, testing truncation occurence, and testing
    truncation detection.

    Additionally, in passing:

     - Removed unused udata argument from H5FDcoordinate.
     - Updated trace file for H5F_avoid_truncate_t type.

Tested:

    h5committest and manually on jam w/ check-vfd.