patch 8.0.1698: coverage statistics don't work on coveralls

Problem:    Coverate statistics don't work on coveralls.
Solution:   Use curly braces for $SRCDIR.
diff --git a/src/version.c b/src/version.c
index bc0e513..5a26ec5 100644
--- a/src/version.c
+++ b/src/version.c
@@ -763,6 +763,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1698,
+/**/
     1697,
 /**/
     1696,