make gRPC buck build script fail fast on error

- See comment in: https://gerrit.onosproject.org/14531
  for more details about the problem.

Change-Id: I7ef3aa92dfa5116a077f3d6878856b555cfda93c
diff --git a/buck-tools/grpc b/buck-tools/grpc
index 6eb5af3..9a8fa27 100755
--- a/buck-tools/grpc
+++ b/buck-tools/grpc
@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/bin/bash -e
 # -----------------------------------------------------------------------------
 # Generates the gRPC java artifacts from protobuf models.
 # -----------------------------------------------------------------------------
diff --git a/incubator/protobuf/models/BUCK b/incubator/protobuf/models/BUCK
index 99619ed..81a9b25 100644
--- a/incubator/protobuf/models/BUCK
+++ b/incubator/protobuf/models/BUCK
@@ -23,6 +23,8 @@
 grpc_jar(
     name = 'onos-incubator-protobuf-models-proto',
     deps = GRPC_DEPS,
+    # FIXME should not be manually building absolute path.
+    # Come up with glob(..) equivalent in BUCK which can handle directory.
     proto_paths = ["$ONOS_ROOT/incubator/protobuf/models/src/main/proto"]
 )
 
diff --git a/incubator/protobuf/services/nb/BUCK b/incubator/protobuf/services/nb/BUCK
index 1d3c697..f2528a4 100644
--- a/incubator/protobuf/services/nb/BUCK
+++ b/incubator/protobuf/services/nb/BUCK
@@ -49,6 +49,8 @@
 grpc_jar(
     name = 'onos-incubator-protobuf-services-nb-proto',
     deps = GRPC_DEPS,
+    # FIXME should not be manually building absolute path
+    # come up with glob(..) equivalent in BUCK which can handle directory
     proto_paths = ["$ONOS_ROOT/incubator/protobuf/services/nb/src/main/proto",
         "$ONOS_ROOT/incubator/protobuf/models/src/main/proto"]
 )
@@ -66,4 +68,4 @@
     included_bundles = ['//incubator/grpc-dependencies:grpc-core-repkg-1.3.0',
             '//lib:google-instrumentation-0.3.0'],
     description = 'gRPC northbound services used to provide fine-grained access to ONOS native northbound interface from off-platform applications',
-)
\ No newline at end of file
+)