Omit bazel.LabelList attrs if no path is specified

Test: go test build_conversion_test.go
Change-Id: Ibcd81049788e99422569fe74e5f3834df4a05122
diff --git a/bp2build/build_conversion_test.go b/bp2build/build_conversion_test.go
index 27212d1..422422b 100644
--- a/bp2build/build_conversion_test.go
+++ b/bp2build/build_conversion_test.go
@@ -469,6 +469,21 @@
 		dir                                string
 	}{
 		{
+			description:                        "filegroup with does not specify srcs",
+			moduleTypeUnderTest:                "filegroup",
+			moduleTypeUnderTestFactory:         android.FileGroupFactory,
+			moduleTypeUnderTestBp2BuildMutator: android.FilegroupBp2Build,
+			bp: `filegroup {
+    name: "fg_foo",
+    bazel_module: { bp2build_available: true },
+}`,
+			expectedBazelTargets: []string{
+				`filegroup(
+    name = "fg_foo",
+)`,
+			},
+		},
+		{
 			description:                        "filegroup with no srcs",
 			moduleTypeUnderTest:                "filegroup",
 			moduleTypeUnderTestFactory:         android.FileGroupFactory,