patch 8.2.0417: Travis CI config can be improved

Problem:    Travis CI config can be improved.
Solution:   Remove COVERAGE variable. Add load-snd-dummy script. add "-i NONE"
            to avoid messages about viminfo. (Ozaki Kiichi, closes #5813)

src/version.c

@@ -738,6 +738,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    417,
 /**/
     416,
 /**/