Description:
    Made printError() virtual as the original; missed it from the previous fix.
Platforms tested:
    Linux/ppc64 (ostrich)
    Linux/32 2.6 (jam)
    SunOS 5.11 (emu)



git-svn-id: https://svn.hdfgroup.uiuc.edu/hdf5/trunk@25125 dab4d1a6-ed17-0410-a064-d1ae371a2980