patch 7.4.2031

Problem:    The list_lbr_utf8 test fails if ~/.vim/syntax/c.vim sets
            'textwidth' to a non-zero value. (Oyvind A. Holm)
Solution:   Add a setup.vim file that sets 'runtimepath' and $HOME to a safe
            value. (partly by Christian Brabandt, closes #912)

src/testdir/unix.vim

@@ -1,3 +1,5 @@
 " Settings for test script execution
 " Always use "sh", don't use the value of "$SHELL".
 set shell=sh
+
+source setup.vim