Fix minor issues with release scripts/documentation
diff --git a/compiler/Dockerfile b/compiler/Dockerfile
index a8f40c5..4994f64 100644
--- a/compiler/Dockerfile
+++ b/compiler/Dockerfile
@@ -10,8 +10,8 @@
     CXXFLAGS=-m64 ./configure --disable-shared --prefix=/protobuf-64 && \
     make clean && make && make install"'
 
-ENV CXXFLAGS -I/protobuf-32/include
-ENV LDFLAGS "-L/protobuf-32/lib -L/protobuf-64/lib"
+ENV CXXFLAGS=-I/protobuf-32/include \
+    LDFLAGS="-L/protobuf-32/lib -L/protobuf-64/lib"
 
 RUN git clone --depth 1 https://github.com/grpc/grpc-java.git