[FIX] Don't break installations that don't have report_xlsx installed

Fixes 287

account_financial_report_qweb/__init__.py

@@ -5,4 +5,15 @@
 
 from . import models
 from . import wizard
-from . import report
+
+# Don't break installations that don't have this module installed
+have_report_xlsx = False
+try:
+    from odoo.addons.report_xlsx.report.report_xlsx import ReportXlsx
+    have_report_xlsx = True
+except ImportError:
+    import logging
+    logging.getLogger(__name__).warn('Module report_xlsx is not available')
+
+if have_report_xlsx:
+    from . import report