remove inline for some functions that IBM XL compiler complains

git-svn-id: https://svn.mcs.anl.gov/repos/parallel-netcdf/trunk@1901 c368ceb8-fd28-0410-a457-e46ee1d7cd4a
ncmpii_abuf_free() will be called in FREE_REQUEST

git-svn-id: https://svn.mcs.anl.gov/repos/parallel-netcdf/trunk@1902 c368ceb8-fd28-0410-a457-e46ee1d7cd4a
revert r1895 and add note on how pnetcdf_libvers and ncmpi_inq_libvers() are used for different purposes

git-svn-id: https://svn.mcs.anl.gov/repos/parallel-netcdf/trunk@1903 c368ceb8-fd28-0410-a457-e46ee1d7cd4a