kbuild: Decode CIP fragment properly, not over str()

CIP configurations was not working, as they was not decoded
properly, looking like `b:'content\notherline\n' instead of
properly formatted kernel config.
Decode() should fix that.

Signed-off-by: Denys Fedoryshchenko <[email protected]>

Author: nuclearcat

kernelci/kbuild.py

@@ -474,7 +474,11 @@ def _getcipfragment(self, fragment):
         buffer = self._download_file(url)
         if not buffer:
             raise FileNotFoundError("Error reading {}".format(url))
-        return str(buffer)
+        try:
+            plain_str = buffer.decode('utf-8')
+        except UnicodeDecodeError:
+            raise ValueError("Error decoding {}".format(url))
+        return plain_str
 
     def _getcrosfragment(self, fragment):
         """ Get ChromeOS specific configuration fragments """