Resolve flaky system test for counting image-rewrites on bursts of requests by allowing 1 or 2 rewrites, instead of requiring 1.  Put in comment explaining that this is due to 'best effort' locks.
Resolve flaky system test for counting image-rewrites on bursts of
requests by allowing 1 or 2 rewrites, instead of requiring 1.  Put in
comment explaining that this is due to 'best effort' locks.

pagespeed/mod_pagespeed,VersoBit/mod_pagespeed,hashashin/src,hashashin/src,VersoBit/mod_pagespeed,hashashin/src,hashashin/src,hashashin/src,pagespeed/mod_pagespeed,VersoBit/mod_pagespeed,pagespeed/mod_pagespeed,VersoBit/mod_pagespeed,pagespeed/mod_pagespeed,VersoBit/mod_pagespeed,VersoBit/mod_pagespeed,hashashin/src,hashashin/src,pagespeed/mod_pagespeed,VersoBit/mod_pagespeed,pagespeed/mod_pagespeed,pagespeed/mod_pagespeed,hashashin/src