avoid echo -e, there are systems where it does not work

FreeBSD 4.11 being one example: the built-in echo doesn't have -e,
and the installed /bin/echo does not do "-e" as well.
"printf" works, laking just "\e" and "\xAB'.

Signed-off-by: Junio C Hamano <junkio@cox.net>

t/t3001-ls-files-others-exclude.sh

@@ -68,7 +68,7 @@ test_expect_success \
      diff -u expect output'
 
 # Test \r\n (MSDOS-like systems)
-echo -ne '*.1\r\n/*.3\r\n!*.6\r\n' >.gitignore
+printf '*.1\r\n/*.3\r\n!*.6\r\n' >.gitignore
 
 test_expect_success \
     'git-ls-files --others with \r\n line endings.' \