deprecation warnings for platform.linux_distribution and pasteURLopener

[smoser]

Hi. I'm using pastebinit on Ubuntu development release (disco) and seeing the following:

$ python3 --version
Python 3.7.1

$ echo foo | ./pastebinit 
./pastebinit:42: DeprecationWarning: dist() and linux_distribution() functions are deprecated in Python 3.5
  release = platform.linux_distribution()[0].lower()
./pastebinit:413: DeprecationWarning: pasteURLopener style of invoking requests is deprecated. Use newer urlopen functions/methods
  url_opener = pasteURLopener()
http://paste.ubuntu.com/p/BzhNQtrZhW/

[mnott]

On the first error, what seems to work is

 41     #import platform                                                             
 42     import distro                                                                
 43     #release = platform.linux_distribution()[0].lower()                          
 44     release = distro.linux_distribution(full_distribution_name=False)