Remove accidental requirement on the worktree content

This made the build impossible since mbedtls isn't available when building
the container.

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
diff --git a/tests/docker/bionic/Dockerfile b/tests/docker/bionic/Dockerfile
index 69662f4..3132be9 100644
--- a/tests/docker/bionic/Dockerfile
+++ b/tests/docker/bionic/Dockerfile
@@ -160,5 +160,3 @@
 
 ENV GNUTLS_NEXT_CLI=/usr/local/gnutls-3.6.5/bin/gnutls-cli
 ENV GNUTLS_NEXT_SERV=/usr/local/gnutls-3.6.5/bin/gnutls-serv
-
-RUN scripts/min_requirements.py