posix: remove is-comparison between integers
Comparing integers by identity relies on a CPython implementation
detail of caching integers between -5 and 256.[1]
[1] <http://docs.python.org/c-api/int.html#PyInt_FromLong>
httprepo: remove is-comparison with string literal
An identity check between a variable and a string literal was added to
the pushkey implementation in
6bd9778ae749. While CPython will
normally intern strings and thus make the test safe, value identity is
what should be used here.