hdf5_ep

[svn-r12183] Purpose:
Configure cleanup

Description:
Removed unused macros, migrated to non-depreciated macros.

Solution:
The changes to use standard AC_TRY_LIB macros earlier this week
seem not to have broken anything, so I deleted the local macros in
acsite.m4 (with an eye to eventually deleting the rest of the file and
using only autoconf-supported macros).
Replaced the depreciated AC_TRY_LIB with AC_LIB_IFELSE to shut up
warnings during reconfigure.

Platforms tested:
mir, copper (should be just cleanup)