examples/ubuntu: fix gyp deprecated option usage

Change-Id: If5eb910456054ce076d7b60007109cfb52162589
Reviewed-on: https://weave-review.googlesource.com/1093
Reviewed-by: Alex Vakulenko <avakulenko@google.com>
Reviewed-by: Vitaly Buka <vitalybuka@google.com>

libweave/examples/ubuntu/build.sh

diff --git a/libweave/examples/ubuntu/build.sh b/libweave/examples/ubuntu/build.sh
index 0f02a17..ea7499f 100755
--- a/libweave/examples/ubuntu/build.sh
+++ b/libweave/examples/ubuntu/build.sh
@@ -8,7 +8,7 @@
 
 cd $ROOT_DIR
 
-gyp -Ilibweave_common.gypi --toplevel-dir=. -f ninja $DIR/weave.gyp
+gyp -Ilibweave_common.gypi --toplevel-dir=. --depth=. -f ninja $DIR/weave.gyp
 
 if [ -z "$BUILD_CONFIG" ]; then
    export BUILD_CONFIG=Debug