CP-9085: Add pylint configuration file.

Signed-off-by: Siddharth Vinothkumar <siddharth.vinothkumar@citrix.com>
CP-9085: Correct undefined variables in StorageHandler.py

Signed-off-by: Siddharth Vinothkumar <siddharth.vinothkumar@citrix.com>
CP-9085: Correct function argument errors in StorageHandler.py

Signed-off-by: Siddharth Vinothkumar <siddharth.vinothkumar@citrix.com>
CP-9085: Fix function redefinition error.

Signed-off-by: Siddharth Vinothkumar <siddharth.vinothkumar@citrix.com>
CP-9085: Fix too many function arguments with StorageHandlerUtil.py

Signed-off-by: Siddharth Vinothkumar <siddharth.vinothkumar@citrix.com>
CP-9085: Import xs_errors module in StorageHandlerUtil.py

Signed-off-by: Siddharth Vinothkumar <siddharth.vinothkumar@citrix.com>
CP-9086: Add travis integration for xencert

- Add .travis.yml
- Add requirements.txt

Signed-off-by: Siddharth Vinothkumar <siddharth.vinothkumar@citrix.com>