Tiny fix for Dockerfile syntax

ISSUE=4590133


git-svn-id: https://svn.baidu.com/idl/trunk/paddle@1418 1ad973e4-5ce8-4261-8a94-b56d1f490c56

paddle/scripts/docker/Dockerfile.m4

@@ -5,7 +5,7 @@ ENV LOWEST_DL_SPEED=0
 ENV WITH_GPU=PADDLE_WITH_GPU
 ENV IS_DEVEL=PADDLE_IS_DEVEL
 ENV WITH_DEMO=PADDLE_WITH_DEMO
-ENV PIP_INSTALL_ARGS
-ENV PIP_GENERAL_ARGS
+ENV PIP_INSTALL_ARGS ""
+ENV PIP_GENERAL_ARGS ""
 ENV CUDNN_DOWNLOAD_SUM 40d506d0a8a00a3faccce1433346806b8cd2535683b6f08a63683ce6e474419f
 RUN cd /root/ && bash build.sh

paddle/scripts/docker/cpu-demo/Dockerfile

@@ -5,7 +5,7 @@ ENV LOWEST_DL_SPEED=0
 ENV WITH_GPU=OFF
 ENV IS_DEVEL=ON
 ENV WITH_DEMO=ON
-ENV PIP_INSTALL_ARGS
-ENV PIP_GENERAL_ARGS
+ENV PIP_INSTALL_ARGS ""
+ENV PIP_GENERAL_ARGS ""
 ENV CUDNN_DOWNLOAD_SUM 40d506d0a8a00a3faccce1433346806b8cd2535683b6f08a63683ce6e474419f
 RUN cd /root/ && bash build.sh

paddle/scripts/docker/cpu-devel/Dockerfile

@@ -5,7 +5,7 @@ ENV LOWEST_DL_SPEED=0
 ENV WITH_GPU=OFF
 ENV IS_DEVEL=ON
 ENV WITH_DEMO=OFF
-ENV PIP_INSTALL_ARGS
-ENV PIP_GENERAL_ARGS
+ENV PIP_INSTALL_ARGS ""
+ENV PIP_GENERAL_ARGS ""
 ENV CUDNN_DOWNLOAD_SUM 40d506d0a8a00a3faccce1433346806b8cd2535683b6f08a63683ce6e474419f
 RUN cd /root/ && bash build.sh

paddle/scripts/docker/cpu/Dockerfile

@@ -5,7 +5,7 @@ ENV LOWEST_DL_SPEED=0
 ENV WITH_GPU=OFF
 ENV IS_DEVEL=OFF
 ENV WITH_DEMO=OFF
-ENV PIP_INSTALL_ARGS
-ENV PIP_GENERAL_ARGS
+ENV PIP_INSTALL_ARGS ""
+ENV PIP_GENERAL_ARGS ""
 ENV CUDNN_DOWNLOAD_SUM 40d506d0a8a00a3faccce1433346806b8cd2535683b6f08a63683ce6e474419f
 RUN cd /root/ && bash build.sh

paddle/scripts/docker/gpu-demo/Dockerfile

@@ -5,7 +5,7 @@ ENV LOWEST_DL_SPEED=0
 ENV WITH_GPU=ON
 ENV IS_DEVEL=ON
 ENV WITH_DEMO=ON
-ENV PIP_INSTALL_ARGS
-ENV PIP_GENERAL_ARGS
+ENV PIP_INSTALL_ARGS ""
+ENV PIP_GENERAL_ARGS ""
 ENV CUDNN_DOWNLOAD_SUM 40d506d0a8a00a3faccce1433346806b8cd2535683b6f08a63683ce6e474419f
 RUN cd /root/ && bash build.sh

paddle/scripts/docker/gpu-devel/Dockerfile

@@ -5,7 +5,7 @@ ENV LOWEST_DL_SPEED=0
 ENV WITH_GPU=ON
 ENV IS_DEVEL=ON
 ENV WITH_DEMO=OFF
-ENV PIP_INSTALL_ARGS
-ENV PIP_GENERAL_ARGS
+ENV PIP_INSTALL_ARGS ""
+ENV PIP_GENERAL_ARGS ""
 ENV CUDNN_DOWNLOAD_SUM 40d506d0a8a00a3faccce1433346806b8cd2535683b6f08a63683ce6e474419f
 RUN cd /root/ && bash build.sh

paddle/scripts/docker/gpu/Dockerfile

@@ -5,7 +5,7 @@ ENV LOWEST_DL_SPEED=0
 ENV WITH_GPU=ON
 ENV IS_DEVEL=OFF
 ENV WITH_DEMO=OFF
-ENV PIP_INSTALL_ARGS
-ENV PIP_GENERAL_ARGS
+ENV PIP_INSTALL_ARGS ""
+ENV PIP_GENERAL_ARGS ""
 ENV CUDNN_DOWNLOAD_SUM 40d506d0a8a00a3faccce1433346806b8cd2535683b6f08a63683ce6e474419f
 RUN cd /root/ && bash build.sh