bugzilla: use util.urlreq.urlparse And stop saving a module variable because it shouldn't be necessary.

pycompat: define urlreq.urlparse and urlreq.unparse aliases Currently, we export urlparse via util.urlparse then call util.urlparse.urlparse() and util.urlparse.urlunparse() in a few places. This is the only url* module exported from pycompat, making it a one-off. So let's transition to urlreq to match everything else. Yes, we double import "urlparse" now on Python 2. This will be cleaned up in a subsequent patch. Also, the Python 3 functions trade in str/unicode not bytes. So we'll likely need to write a custom implementation that speaks bytes. But moving everyone to an abstracted API is a good first step.

pycompat: remove urlunquote alias It is duplicated by urlreq.unquote and is unused. Kill it. We retain the imports because it is re-exported via util.urlparse, which is used elsewhere. Since we no longer access attributes of urlparse at module load time, this change /should/ result in that module reverting to a lazy module.

util: use urlreq.unquote pycompat.urlreq.unquote and pycompat.urlunquote effectively alias the same thing. pycompat.urlunquote is only used once in the code base. So let's switch to urlreq.unquote. "Effectively" in the above paragraph is because pycompat.urlreq.unquote aliases urllib.unquote and pycompat.urlunquote aliases urlparse.unquote on Python 2. You might think one of urllib.unquote and urlparse.unquote is an alias to the other, but you would be incorrect. In fact, these functions are copies of each other. There is even a comment in the CPython source code saying to keep them in sync. You can't make this up.