Get dashboard working on Mac by commenting out one more null user check.
Get dashboard working on Mac by commenting out one more null user check.

Also introduce some logging to help in troubleshooting and some minor
cleanups like using json.dumps().


git-svn-id: abd770af2affaf62930f25b244f6edafe8ddae5b@111 164481a5-15cb-f69f-4b93-856c5b7754c5

ting-yuan/web-page-replay,ting-yuan/web-page-replay,chromium/web-page-replay,snorp/web-page-replay,colin-scott/web-page-replay,chromium/web-page-replay,bpsinc-native/src_third_party_webpagereplay,snorp/web-page-replay,colin-scott/web-page-replay,andrey-malets/web-page-replay,bpsinc-native/src_third_party_webpagereplay,andrey-malets/web-page-replay,bpsinc-native/src_third_party_webpagereplay