Add rule for pip_install permission fix (#895)

* Add rule for pip_install permission fix

* Fix whitespace

* Switch quotation to single

* remove 2nd else

* E261 indent comment

thefuck/rules/pip_install.py

@@ -0,0 +1,15 @@
+from thefuck.utils import for_app
+from thefuck.specific.sudo import sudo_support
+
+
+@sudo_support
+@for_app('pip')
+def match(command):
+    return ('pip install' in command.script and 'Permission denied' in command.output)
+
+
+def get_new_command(command):
+    if '--user' not in command.script:  # add --user (attempt 1)
+        return command.script.replace(' install ', ' install --user ')
+
+    return 'sudo {}'.format(command.script.replace(' --user', ''))  # since --user didn't fix things, let's try sudo (attempt 2)