use simpler super() magic

Python 3 has a simpler super() style so switch to it to make the
code a little simpler and to stop pylint warnings.

Change-Id: I1b3ccf57ae968d56a9a0bcfc1258fbd8bfa3afee
Reviewed-on: https://gerrit-review.googlesource.com/c/git-repo/+/297383
Reviewed-by: Michael Mortensen <mmortensen@google.com>
Tested-by: Mike Frysinger <vapier@google.com>
diff --git a/error.py b/error.py
index 20d5f72..2fb6aa0 100644
--- a/error.py
+++ b/error.py
@@ -37,7 +37,7 @@
   """
 
   def __init__(self, path, reason):
-    super(NoManifestException, self).__init__(path, reason)
+    super().__init__(path, reason)
     self.path = path
     self.reason = reason
 
@@ -50,7 +50,7 @@
   """
 
   def __init__(self, reason):
-    super(EditorError, self).__init__(reason)
+    super().__init__(reason)
     self.reason = reason
 
   def __str__(self):
@@ -62,7 +62,7 @@
   """
 
   def __init__(self, command):
-    super(GitError, self).__init__(command)
+    super().__init__(command)
     self.command = command
 
   def __str__(self):
@@ -74,7 +74,7 @@
   """
 
   def __init__(self, reason):
-    super(UploadError, self).__init__(reason)
+    super().__init__(reason)
     self.reason = reason
 
   def __str__(self):
@@ -86,7 +86,7 @@
   """
 
   def __init__(self, reason):
-    super(DownloadError, self).__init__(reason)
+    super().__init__(reason)
     self.reason = reason
 
   def __str__(self):
@@ -98,7 +98,7 @@
   """
 
   def __init__(self, name=None):
-    super(NoSuchProjectError, self).__init__(name)
+    super().__init__(name)
     self.name = name
 
   def __str__(self):
@@ -112,7 +112,7 @@
   """
 
   def __init__(self, name=None):
-    super(InvalidProjectGroupsError, self).__init__(name)
+    super().__init__(name)
     self.name = name
 
   def __str__(self):
@@ -128,7 +128,7 @@
   """
 
   def __init__(self, extra_args=None):
-    super(RepoChangedException, self).__init__(extra_args)
+    super().__init__(extra_args)
     self.extra_args = extra_args or []