Make dtrace and logman tracer recover on trace failure.
Make dtrace and logman tracer recover on trace failure.

This permits reading other traces even if one fails. This can occur under
specific circumstances.

Sort dict elements by key name.

R=csharp@chromium.org
BUG=


Review URL: https://chromiumcodereview.appspot.com/11346011

git-svn-id: d5a9b8648c52d490875de6588c8ee7ca688f9ed1@164677 0039d316-1c4b-4281-b951-d872f2087c98

luci/luci-py,luci/luci-py,luci/luci-py,luci/luci-py