Contrib: do not build Jaeger example apps.

contrib/src/jaeger-client-cpp/Makefile

diff --git a/contrib/src/jaeger-client-cpp/Makefile b/contrib/src/jaeger-client-cpp/Makefile
index 1b4dd4e..6efd179 100644
--- a/contrib/src/jaeger-client-cpp/Makefile
+++ b/contrib/src/jaeger-client-cpp/Makefile
@@ -30,6 +30,7 @@
 		OpenTracing_DIR=$(PREFIX)/usr/local/lib/cmake/OpenTracing \
 		thrift_DIR=$(PREFIX)/usr/local/lib/cmake/thrift \
 		$(CMAKE) \
+			-DJAEGERTRACING_BUILD_EXAMPLES=OFF \
 			-DBUILD_TESTING=OFF \
 			-DJAEGERTRACING_PLUGIN=ON \
 			-DCMAKE_BUILD_TYPE=Release \