8.0 Use try/except when importing external libs (#8)

[FIX] LINT

Use try/except when importing external libs
Remove self.ensure_one() that has nothing to do in an api.model method

base_business_document_import/models/business_document_import.py

@@ -5,15 +5,18 @@
 from openerp import models, api, _
 from openerp.tools import float_compare
 from openerp.exceptions import Warning as UserError
-import PyPDF2
 from lxml import etree
 from StringIO import StringIO
 import mimetypes
 from urlparse import urlparse
 import logging
-
 logger = logging.getLogger(__name__)
 
+try:
+    import PyPDF2
+except ImportError:
+    logger.debug('Cannot import PyPDF2')
+
 
 class BusinessDocumentImport(models.AbstractModel):
     _name = 'business.document.import'