tests: change `...' to '...' on lines not matching /[=\$]/

Exempt lines with '$' or '=', since those are prone to improper
conversion.  Run this:
  git grep -l "\`[^']*'" tests \
   |xargs perl -pi -e '/[=\$]/ and next;s/\`([^'\''"]*?'\'')/'\''$1/g'

1 files changed, 2 insertions, 2 deletions

diff --git a/tests/tail-2/F-vs-missing b/tests/tail-2/F-vs-missing
index 194b55943..fbdb53314 100755
--- a/tests/tail-2/F-vs-missing
+++ b/tests/tail-2/F-vs-missing
@@ -33,14 +33,14 @@ check_tail_output()
 }
 
 # Wait up to 6.3s for tail to start with diagnostic:
-# tail: cannot open `missing/file' for reading: No such file or directory
+# tail: cannot open 'missing/file' for reading: No such file or directory
 tail_re='cannot open' retry_delay_ check_tail_output .1 7 || fail=1
 
 mkdir missing || fail=1
 (cd missing && echo x > file)
 
 # Wait up to 6.3s for this to appear in the output:
-# "tail: `...' has appeared;  following end of new file"
+# "tail: '...' has appeared;  following end of new file"
 tail_re='has appeared' retry_delay_ check_tail_output .1 7 ||
   { echo "$0: file: unexpected delay?"; cat out; fail=1; }