shill: Use shill's set-apn-helper rather than flimflam's.

BUG=chromium-os:35363
TEST=set_apn on the device

Change-Id: I06ff1a2e28e1658bfeaa6536f48448f160ad5940
Reviewed-on: https://gerrit.chromium.org/gerrit/36426
Tested-by: Darin Petkov <petkov@chromium.org>
Reviewed-by: Ben Chan <benchan@chromium.org>
Reviewed-by: Paul Stewart <pstew@chromium.org>
Commit-Ready: Darin Petkov <petkov@chromium.org>
diff --git a/bin/set_apn b/bin/set_apn
index 8d181df..717026d 100755
--- a/bin/set_apn
+++ b/bin/set_apn
@@ -32,7 +32,7 @@
 if [ ! -d "${LIBDIR}" ]; then
   LIBDIR=/usr/lib
 fi
-SET_APN_HELPER=${LIBDIR}/flimflam/scripts/set_apn_helper
+SET_APN_HELPER=${LIBDIR}/shill/shims/set-apn-helper
 
 usage() {
   echo $*