Detect HDF5_DIR in environment.
Detect HDF5_DIR in environment.

This is similar to what we do for other packages (PETSc, VTK, etc.)
but was not implemented for HDF5.  Also add message when HDF5 support
is not found.

capitalaslash/libmesh,balborian/libmesh,benkirk/libmesh,giorgiobornia/libmesh,capitalaslash/libmesh,balborian/libmesh,libMesh/libmesh,aeslaughter/libmesh,aeslaughter/libmesh,friedmud/libmesh,BalticPinguin/libmesh,balborian/libmesh,coreymbryant/libmesh,svallaghe/libmesh,jwpeterson/libmesh,friedmud/libmesh,giorgiobornia/libmesh,aeslaughter/libmesh,pbauman/libmesh,90jrong/libmesh,vikramvgarg/libmesh,hrittich/libmesh,capitalaslash/libmesh,pbauman/libmesh,coreymbryant/libmesh,roystgnr/libmesh,90jrong/libmesh,roystgnr/libmesh,coreymbryant/libmesh,balborian/libmesh,balborian/libmesh,vikramvgarg/libmesh,pbauman/libmesh,dschwen/libmesh,libMesh/libmesh,aeslaughter/libmesh,roystgnr/libmesh,dschwen/libmesh,capitalaslash/libmesh,giorgiobornia/libmesh,coreymbryant/libmesh,roystgnr/libmesh,balborian/libmesh,friedmud/libmesh,balborian/libmesh,90jrong/libmesh,vikramvgarg/libmesh,svallaghe/libmesh,giorgiobornia/libmesh,90jrong/libmesh,BalticPinguin/libmesh,jwpeterson/libmesh,pbauman/libmesh,svallaghe/libmesh,giorgiobornia/libmesh,friedmud/libmesh,vikramvgarg/libmesh,svallaghe/libmesh,vikramvgarg/libmesh,benkirk/libmesh,jwpeterson/libmesh,svallaghe/libmesh,coreymbryant/libmesh,hrittich/libmesh,svallaghe/libmesh,libMesh/libmesh,hrittich/libmesh,svallaghe/libmesh,benkirk/libmesh,roystgnr/libmesh,hrittich/libmesh,aeslaughter/libmesh,hrittich/libmesh,vikramvgarg/libmesh,benkirk/libmesh,90jrong/libmesh,pbauman/libmesh,balborian/libmesh,roystgnr/libmesh,coreymbryant/libmesh,roystgnr/libmesh,jwpeterson/libmesh,hrittich/libmesh,pbauman/libmesh,aeslaughter/libmesh,BalticPinguin/libmesh,dschwen/libmesh,libMesh/libmesh,pbauman/libmesh,capitalaslash/libmesh,pbauman/libmesh,libMesh/libmesh,hrittich/libmesh,coreymbryant/libmesh,BalticPinguin/libmesh,90jrong/libmesh,balborian/libmesh,90jrong/libmesh,libMesh/libmesh,friedmud/libmesh,dschwen/libmesh,svallaghe/libmesh,benkirk/libmesh,dschwen/libmesh,roystgnr/libmesh,benkirk/libmesh,capitalaslash/libmesh,hrittich/libmesh,giorgiobornia/libmesh,vikramvgarg/libmesh,friedmud/libmesh,jwpeterson/libmesh,jwpeterson/libmesh,balborian/libmesh,BalticPinguin/libmesh,aeslaughter/libmesh,friedmud/libmesh,aeslaughter/libmesh,dschwen/libmesh,jwpeterson/libmesh,benkirk/libmesh,giorgiobornia/libmesh,giorgiobornia/libmesh,dschwen/libmesh,90jrong/libmesh,BalticPinguin/libmesh,dschwen/libmesh,vikramvgarg/libmesh,benkirk/libmesh,giorgiobornia/libmesh,pbauman/libmesh,benkirk/libmesh,capitalaslash/libmesh,libMesh/libmesh,libMesh/libmesh,svallaghe/libmesh,90jrong/libmesh,vikramvgarg/libmesh,BalticPinguin/libmesh,friedmud/libmesh,coreymbryant/libmesh,friedmud/libmesh,capitalaslash/libmesh,hrittich/libmesh,BalticPinguin/libmesh,jwpeterson/libmesh,aeslaughter/libmesh