Enable code coverage

To enable: './configure --enable-code-coverage'

To build and generate report: 'make check-code-coverage'

Tested:
Verified that 'make check-code-coverage' generates lcov report.

Signed-off-by: Priyanga <priyram1@in.ibm.com>
Change-Id: I36a9b501c441ef25595808ce77fc1ca36c1ac323