Fix pylint errors

Fix the pylint errors. e.g. useless-object-inheritance, super-with-arguments,
unnecessary-comprehension, and no-else-return.

Bug: 195474743
Test: acloud-dev create
Change-Id: Ia778cc4d7a05678b099cdbd146c9e762fd68437e
diff --git a/setup/google_sdk.py b/setup/google_sdk.py
index 1343a3d..e216228 100644
--- a/setup/google_sdk.py
+++ b/setup/google_sdk.py
@@ -77,16 +77,16 @@
     if is_64bits:
         if os_type == LINUX:
             return LINUX_GCP_SDK_64_URL
-        elif os_type == MAC:
+        if os_type == MAC:
             return MAC_GCP_SDK_64_URL
-        elif os_type == WIN:
+        if os_type == WIN:
             return WIN_GCP_SDK_64_URL
     else:
         if os_type == LINUX:
             return LINUX_GCP_SDK_32_URL
-        elif os_type == MAC:
+        if os_type == MAC:
             return MAC_GCP_SDK_32_URL
-        elif os_type == WIN:
+        if os_type == WIN:
             return WIN_GCP_SDK_32_URL
     raise errors.OSTypeError("no gcloud for os type: %s" % (os_type))
 
@@ -105,7 +105,7 @@
     return False
 
 
-class GoogleSDK(object):
+class GoogleSDK():
     """Google SDK tools installer."""
 
     def __init__(self):
@@ -155,7 +155,7 @@
         builtin_gcloud = utils.FindExecutable(GCLOUD_BIN)
         if builtin_gcloud:
             return os.path.dirname(builtin_gcloud)
-        elif os.path.exists(self._tmp_sdk_path):
+        if os.path.exists(self._tmp_sdk_path):
             return self._tmp_sdk_path
         raise errors.NoGoogleSDKDetected("no sdk path.")