Fix mixed indent in bootstrap

Tabs or spaces... I believe the policy on ct-ng is spaces for shell
scripts. So update bootstrap to stick to 4 space indent.

Signed-off-by: Bryan Hundven <bryanhundven@gmail.com>

bootstrap

@@ -1,4 +1,5 @@
 #!/usr/bin/env bash
+# vi: ts=4:sw=4:et
 
 if [ "${BASH_VERSINFO[0]}" -lt 4 ]; then
     echo "Your BASH shell version (${BASH_VERSION}) is too old." >&2
@@ -823,7 +824,7 @@ msg "*** Gathering the list of data files to install"
             continue
         fi
         echo " \\"
-        echo -n "	${f}"
+        echo -en "\t${f}"
         seen_files[${f}]=y
     done
 } > verbatim-data.mk