Fixed another scheme proxy over "all" priority

requests/sessions.py

@@ -226,7 +226,7 @@ class SessionRedirectMixin(object):
         if self.trust_env and not should_bypass_proxies(url):
             environ_proxies = get_environ_proxies(url)
 
-            proxy = environ_proxies.get('all', environ_proxies.get(scheme))
+            proxy = environ_proxies.get(scheme, environ_proxies.get('all'))
 
             if proxy:
                 new_proxies.setdefault(scheme, proxy)

requests/utils.py

@@ -617,7 +617,7 @@ def select_proxy(url, proxies):
     proxies = proxies or {}
     urlparts = urlparse(url)
     if urlparts.hostname is None:
-        return proxies.get('all', proxies.get(urlparts.scheme))
+        return proxies.get(urlparts.scheme, proxies.get('all'))
 
     proxy_keys = [
         urlparts.scheme + '://' + urlparts.hostname,

tests/test_utils.py

@@ -343,7 +343,7 @@ mixed_proxies = {'http': 'http://http.proxy',
         ('http://u:p@some.host/path', 'http://some.host.proxy', mixed_proxies),
         ('https://u:p@other.host/path', 'socks5://http.proxy', mixed_proxies),
         ('https://u:p@some.host/path', 'socks5://http.proxy', mixed_proxies),
-        
+        ('https://', 'socks5://http.proxy', mixed_proxies),
         # XXX: unsure whether this is reasonable behavior
         ('file:///etc/motd', 'socks5://http.proxy', all_proxies),
     ))