add .gitignore

Add .gitignore to hide generated objects.

Change-Id: If811483c866e861eeadfa43e7d20c561ac6ac001
Signed-off-by: Patrick Venture <venture@google.com>

Add gitignore file

Change-Id: Id1632050e9c294d1578f970f16eecd4c90398926
Signed-off-by: Murulidhar Nataraju <murulidhar@in.ibm.com>