Correct expectation in DHM test in ssl-opt.sh

The previous test expected a DHM group generator of size 2048 bits, while with
the change to RFC 7919, the base is 2, so has bit-size 2.
diff --git a/tests/ssl-opt.sh b/tests/ssl-opt.sh
index 280fc63..de20588 100755
--- a/tests/ssl-opt.sh
+++ b/tests/ssl-opt.sh
@@ -2903,7 +2903,7 @@
                     debug_level=3" \
             0 \
             -c "value of 'DHM: P ' (2048 bits)" \
-            -c "value of 'DHM: G ' (2048 bits)"
+            -c "value of 'DHM: G ' (2 bits)"
 
 run_test    "DHM parameters: other parameters" \
             "$P_SRV dhm_file=data_files/dhparams.pem" \