Dear Manimaran,
Not a problem. It looks like you installed deal.II correctly but you will have to compile it again to link it with HDF5.
I recommend using apt to install HDF5; run
sudo apt-get install libhdf5-dev
at the command line to get a copy of HDF5 (that can be used for development, hence the -dev suffix) installed on your computer. Once its installed you should delete the deal.II build directory and compile it again (doing what you did before); it should automatically detect the copy of HDF5 you just installed (you can double-check this by reading the output file detailed.log).
Does this make sense? Let me know if you have more questions.
Thanks,
David Wells