patch 8.0.1515: BufWinEnter event fired when opening hidden terminal

Problem:    BufWinEnter event fired when opening hidden terminal.
Solution:   Do not fire BufWinEnter when the terminal is midden and does not
            open a window. (Kenta Sato, closes #2636)
diff --git a/src/version.c b/src/version.c
index adedd85..52479de 100644
--- a/src/version.c
+++ b/src/version.c
@@ -772,6 +772,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1515,
+/**/
     1514,
 /**/
     1513,