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)
diff --git a/src/version.c b/src/version.c
index 2949f05..349c679 100644
--- a/src/version.c
+++ b/src/version.c
@@ -739,6 +739,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    417,
+/**/
     416,
 /**/
     415,