[source] base-files: don't overwrite model name set by target

[LEDE Commits]

mkresin pushed a commit to source.git, branch lede-17.01:
https://git.lede-project.org/b2437a02a45f80cdcee2313e754cc54d92061987

commit b2437a02a45f80cdcee2313e754cc54d92061987
Author: Mathias Kresin <dev at kresin.me>
AuthorDate: Sat Jan 28 16:19:35 2017 +0100

    base-files: don't overwrite model name set by target
    
    The condition is always true due to the literal string followed the
    -n test parameter. A model name set by target scripts always gets
    overwritten this way.
    
    Change the condition to check for an already existing destination file
    as it was before 5e85ae9 ("base-files: fix error message during boot").
    
    Signed-off-by: Mathias Kresin <dev at kresin.me>
---
 package/base-files/files/lib/preinit/10_sysinfo | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/package/base-files/files/lib/preinit/10_sysinfo b/package/base-files/files/lib/preinit/10_sysinfo
index be1e6ae..65b5096 100644
--- a/package/base-files/files/lib/preinit/10_sysinfo
+++ b/package/base-files/files/lib/preinit/10_sysinfo
@@ -3,7 +3,7 @@ do_sysinfo_generic() {
 	mkdir -p /tmp/sysinfo
 	[ -e /tmp/sysinfo/board_name ] || \
 		echo "$(strings /proc/device-tree/compatible | head -1)" > /tmp/sysinfo/board_name
-	[ -n /tmp/sysinfo/model -a -e /proc/device-tree/model ] && \
+	[ ! -e /tmp/sysinfo/model -a -e /proc/device-tree/model ] && \
 		echo "$(cat /proc/device-tree/model)" > /tmp/sysinfo/model
 }