include version, commit, and android tools versions in local log

This includes more info to help track down problems with reproducible
builds, like the specific version being built, and which exact versions of
the Android SDK and NDK were used.

fdroidserver/build.py

@@ -1186,6 +1186,12 @@ def main():
                 wikilog = str(vcse)
             except FDroidException as e:
                 with open(os.path.join(log_dir, appid + '.log'), 'a+') as f:
+                    f.write('\n\n============================================================\n')
+                    f.write('versionCode: %s\nversionName: %s\ncommit: %s\n' %
+                            (build.vercode, build.version, build.commit))
+                    f.write('Build completed at '
+                            + time.strftime("%Y-%m-%d %H:%M:%SZ", time.gmtime()) + '\n')
+                    f.write('\n' + tools_version_log + '\n')
                     f.write(str(e))
                 logging.error("Could not build app %s: %s" % (appid, e))
                 if options.stop: