Some systems, like AIX poe, interpret exit(134) the same as if the process has
really been interrupted by the abort signal and prints extra messages that
confuse test script which is looking for matching output.
Solution:
Changed it to exit(6) which still has the "appearance" of an abort signal which
carries the value of 6 in Unix systems.
Tested: LLNL Up both serial and Parallel.
Changed H5check_version() to suppress the warning message totally if
$HDF5_DISABLE_VERSION_CHECK is 2 or higher. (Old behavior treated 3 or higher
the same as 1, that is to print a warning and allows the program to continue.
Tested:
h5committested, extra jam serial, --disable-embedded-libinfo.
Add new tests (tcheck_version, testcheck_version.sh) to verify H5check_version()
does issue warnings and abort accordingly.
Tests:
H5committed tested plus jam serial tested.
