fate: rename fate-mov-init-nonkeyframe ref file

Fixes the test. Regression since 059a786c20201fe4040738c99b02cca0cfc18a74

Signed-off-by: James Almer <jamrial@gmail.com>

diff --git a/tests/ref/fate/mp4-init-nonkeyframe b/tests/ref/fate/mov-init-nonkeyframe
similarity index 100%
rename from tests/ref/fate/mp4-init-nonkeyframe
rename to tests/ref/fate/mov-init-nonkeyframe