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>

src/testdir/test_options.vim

@@ -1168,11 +1168,14 @@ func Test_backupskip()
     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
 

src/version.c

@@ -704,6 +704,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1312,
 /**/
     1311,
 /**/