Fix build issue in protoc container
Change-Id: I3a83ccf087f79e66902f94af3097f76f06b964d0
diff --git a/docker/Dockerfile.protoc b/docker/Dockerfile.protoc
index f9cd10f..eef6f54 100644
--- a/docker/Dockerfile.protoc
+++ b/docker/Dockerfile.protoc
@@ -31,7 +31,7 @@
ENV PROTOC_DOWNLOAD_URI=${PROTOC_DOWNLOAD_PREFIX}/v${PROTOC_VERSION}/${PROTOC_TARBALL}
RUN apt-get update -y && apt-get install -y wget build-essential python-dev python-pip
-RUN pip install --upgrade pip && pip install grpcio-tools==1.3.5
+RUN pip install grpcio-tools==1.3.5
WORKDIR /build
RUN wget -q --no-check-certificate ${PROTOC_DOWNLOAD_URI}
RUN tar --strip-components=1 -zxf ${PROTOC_TARBALL}