global: convert indentation-TABs to spaces

Transformed via this shell code:
t=$'\t'
git ls-files \
  | grep -vE '(^|/)((GNU)?[Mm]akefile|ChangeLog)|\.(am|mk)$' \
  | grep -vE 'tests/pr/|help2man' \
  | xargs grep -lE "^ *$t" \
  | xargs perl -MText::Tabs -ni -le \
    '$m=/^( *\t[ \t]*)(.*)/; print $m ? expand($1) . $2 : $_'

tests/touch/dangling-symlink

@@ -39,13 +39,13 @@ if test $fail = 1; then
     *linux-gnu*)
       case "`uname -r`" in
         2.3.9[0-9]*)
-	  skip_test_ \
+          skip_test_ \
 '****************************************************
 WARNING!!!
 This version of the Linux kernel causes touch to fail
 when operating on dangling symlinks.
 ****************************************************'
-	  ;;
+          ;;
       esac
       ;;
   esac