fixup! releasetools: support reading release keys out of some sort of command

subprocess no longer outputs strings thus we got to use decode('utf-8')

Change-Id: Ia8ead82cf6b2beded4c53a078126512f44e50cf2

tools/releasetools/common.py

@@ -2161,7 +2161,7 @@ class PasswordManager(object):
               ps = subprocess.Popen(self.secure_storage_cmd, shell=True, stdout=subprocess.PIPE)
               output = ps.communicate()[0]
               if ps.returncode == 0:
-                current[i] = output
+                current[i] = output.decode('utf-8')
             except Exception as e:
               print(e)
               pass