patch 8.0.1122: vimtutor.bat doesn't work well with vim.bat

Problem:    vimtutor.bat doesn't work well with vim.bat.
Solution:   Use "call vim". (Ken Takata, closes #2105)
diff --git a/src/version.c b/src/version.c
index e215d3e..a241166 100644
--- a/src/version.c
+++ b/src/version.c
@@ -762,6 +762,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1122,
+/**/
     1121,
 /**/
     1120,
diff --git a/vimtutor.bat b/vimtutor.bat
index b147a8c..a670b0e 100644
--- a/vimtutor.bat
+++ b/vimtutor.bat
@@ -47,11 +47,11 @@
 
 :use_vim
 :: The script tutor.vim tells Vim which file to copy
-vim -u NONE -c "so $VIMRUNTIME/tutor/tutor.vim"
+call vim -u NONE -c "so $VIMRUNTIME/tutor/tutor.vim"
 IF ERRORLEVEL 1 GOTO no_executable
 
 :: Start vim without any .vimrc, set 'nocompatible'
-vim -u NONE -c "set nocp" %TUTORCOPY%
+call vim -u NONE -c "set nocp" %TUTORCOPY%
 
 GOTO end