test1422: add required file feature

curl configured with --enable-debug --disable-file currently complains
on test1422:
Info: Protocol "file" not supported or disabled in libcurl

Make test1422 dependend on enabled FILE protocol to fix this.

Fixes #2741
Closes #2742

tests/data/test1422

@@ -28,6 +28,7 @@ Content-Disposition: filename=name1422; charset=funny; option=str//nge
 # -O and -J output in, using the CURL_TESTDIR variable
 <features>
 debug
+file
 </features>
 <server>
 http