Fix call bug...

Signed-off-by: René Jochum <rene@jochum.dev>

docker-entrypoint.py

@@ -35,7 +35,7 @@ for dovecot_file in glob.glob("/overrides/**/*.jinja", recursive=True):
     os.chmod(out_path, 600)
 
 if not os.path.isfile("/data/dh.pem"):
-    subprocess.call("/usr/bin/openssl", "dhparam", "-out", "/data/dh.pem", "4096")
+    subprocess.call(["/usr/bin/openssl", "dhparam", "-out", "/data/dh.pem", "4096"])
 
 subprocess.call(["/bin/mkdir", "-p", "/data/vmail"])
 subprocess.call(["/bin/chmod", "u=rwX,g=rX,o=rX", "/data"])