check-code: drop the `safehasattr` rule Since we no longer supports Python 2 we no longer needs to use a custom function to compensate the short comings of the global `hasattr` function in it. We cannot use the Python 3 `hasattr` function instead.

url: ignore some future pytype error As soon as we start using the builtins `hasattr` function, pytype will start getting confused about which types are available or not. So we ignore this error beforehand.

url: move the _generic_proxytunnel in the `has_https` block It is only used when https exists. If you stay out of the block, pytype complains that the type of its argument are not declared.

pycompat: deprecate using bytes Python2 has been dropped for a while, so lets comply to the signature of the global function. This open the way to drop the use of `pycompat.getattr` and company, and, especially, the associated `util.safehasattr`.

dynamic-import: use sysstr for importing extension and others This logic is used by extensions, and python hooks and merge-tools. All this logic eventually deals with native string (unicode in Python 3). This patch makes it handle `str` directly instead of relying on some pycompat low lever layer to do the conversion at the last minutes. We adjust the Python version filtering of a test as the output seems to be present with Python 3.7 too.

extension: check the command attributes using `sysstr` Since we are checking attributes, lets use the native representation instead of bytes.

extension: access special module members using sysstr These extensions variables and mapping are module attributes so they should be dealt with unicode `str` in Python 3. We move the part that deal with reading theses variable and checking their validity to use unicode `str` string.

sshpeer: convert command name to sysstr before accessing method Method name are `str` so we should pass them as `str`.