17.0.1 imminent

Mozilla is planning to ship a 17.0.1 to fix several regressions in 17.0, including bug 815359's problem with Bing, restoring the old user agent format, and a font regression on Windows that doesn't affect us. The plan is to go to build as early as today (I'm not sure when it will be released, exactly). This is a little inconvenient because Tobias wrote some additional performance patches in issue 191, our atomics/mutex performance bug, which look good and appear to work even on the quad G5 (which you would expect to have the most problems if we did something wrong with barriers). So I'm going to cross my fingers and make them part of 17.0.1 since it's a little complex to back them out now. I'm rebuilding everything as soon as build tags land on esr17 and hopefully candidate builds will be available Thursday evening or early Friday.