[IMP] Protect import of external lib to prevent error when the module…

… is put in an addons path without the external lib installed

This error should never occur since if you put this project into your addon path you want to use it and without the lib it don't work. But Travis CI fails if these imports are not protected due to a stupid rule enforced in odoo-pylint (Oct, 11, 2016) OCA/maintainer-quality-tools#354

cmis/models/cmis_backend.py

@@ -4,10 +4,6 @@
 # License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl.html).
 
 import logging
-import cmislib.exceptions
-from cmislib.model import CmisClient
-from cmislib.browser.binding import BrowserBinding
-from cmislib.exceptions import ObjectNotFoundException
 
 from openerp import api, fields, models
 from openerp.exceptions import UserError
@@ -16,6 +12,14 @@
 
 _logger = logging.getLogger(__name__)
 
+try:
+    import cmislib.exceptions
+    from cmislib.model import CmisClient
+    from cmislib.browser.binding import BrowserBinding
+    from cmislib.exceptions import ObjectNotFoundException
+except (ImportError, IOError) as err:
+    _logger.debug(err)
+
 
 class CmisBackend(models.Model):
     _name = 'cmis.backend'