resulttool/report: Avoid divide by zero

Avoid a divide by zero traceback if unfortunate test counts are encountered.

(From OE-Core rev: 33d3374a7149ad1afe86d86c0dc2a948f70e26bd)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
(cherry picked from commit c5aeea53dfacb53dedb8445cb3523dc3a8cb6dca)
Signed-off-by: Steve Sakoman <steve@sakoman.com>

scripts/lib/resulttool/report.py

@@ -176,7 +176,10 @@ class ResultsTextReport(object):
             vals['sort'] = line['testseries'] + "_" + line['result_id']
             vals['failed_testcases'] = line['failed_testcases']
             for k in cols:
-                vals[k] = "%d (%s%%)" % (line[k], format(line[k] / total_tested * 100, '.0f'))
+                if total_tested:
+                    vals[k] = "%d (%s%%)" % (line[k], format(line[k] / total_tested * 100, '.0f'))
+                else:
+                    vals[k] = "0 (0%)"
             for k in maxlen:
                 if k in vals and len(vals[k]) > maxlen[k]:
                     maxlen[k] = len(vals[k])