Define title outside the loop

If languages is empty for Report.get_email, the title is used before
assignation.

issue7499
review47501002

trytond/report/report.py

@@ -374,6 +374,7 @@ def get_email(report, record, languages):
             report_name = report
         Report_ = pool.get(report_name, type='report')
     converter = None
+    title = None
     msg = MIMEMultipart('alternative')
     msg.add_header('Content-Language', ', '.join(l.code for l in languages))
     for language in languages: