patch 9.1.1312: tests: Test_backupskip() fails when HOME is defined

Problem:  tests: Test_backupskip() fails when HOME is defined
Solution: unset $HOME temporarily

Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/testdir/test_options.vim b/src/testdir/test_options.vim
index d8ad3f2..9708fcc 100644
--- a/src/testdir/test_options.vim
+++ b/src/testdir/test_options.vim
@@ -1168,11 +1168,14 @@
     call setenv(var, '/duplicate/path')
   endfor
 
+  " unset $HOME, so that it won't try to read init files
+  let saveenv['HOME'] = getenv("HOME")
+  call setenv('HOME', v:null)
   exe 'silent !' . cmd
   call assert_equal(['errors:'], readfile('Xtestout'))
 
   " restore environment variables
-  for var in ['TMPDIR', 'TMP', 'TEMP']
+  for var in ['TMPDIR', 'TMP', 'TEMP', 'HOME']
     call setenv(var, saveenv[var])
   endfor
 
diff --git a/src/version.c b/src/version.c
index 7aae2b5..2a51b42 100644
--- a/src/version.c
+++ b/src/version.c
@@ -705,6 +705,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1312,
+/**/
     1311,
 /**/
     1310,