simple: miscellaneous fixes

1. Remove references to print_test_hdr.
2. Update FI_PROV_MR_KEY to FI_PROV_MR_ATTR.
3. Return for getaddr failure case.

Signed-off-by: Arun C Ilango <arun.ilango@intel.com>
simple: fi_cntr example.

This patch adds an example for fi_cntr usage.

Signed-off-by: Arun C Ilango <arun.ilango@intel.com>
Merge pull request #70 from a-ilango/add_examples

Some misc fixes and fi_cntr example