Increase the default token key size

The previous default token key size would fail in FIPS mode for the sha384
and sha512 algorithms. With the updated key size, the default will work in
all cases.

https://pagure.io/freeipa/issue/7168

Reviewed-By: Rob Crittenden <rcritten@redhat.com>

ipaserver/plugins/otptoken.py

@@ -72,7 +72,7 @@
 }
 
 # NOTE: For maximum compatibility, KEY_LENGTH % 5 == 0
-KEY_LENGTH = 20
+KEY_LENGTH = 35
 
 class OTPTokenKey(Bytes):
     """A binary password type specified in base32."""