updated Dockerfile to include ioctl copy (iotexproject#631)

Author: jerkyrs

Dockerfile

@@ -11,6 +11,7 @@ RUN mkdir -p $GOPATH/pkg/linux_amd64/github.com/iotexproject/ && \
     cp $GOPATH/src/github.com/iotexproject/iotex-core/bin/server /usr/local/bin/iotex-server  && \
     cp $GOPATH/src/github.com/iotexproject/iotex-core/bin/actioninjectorv2 /usr/local/bin/iotex-actioninjectorv2 && \
     cp $GOPATH/src/github.com/iotexproject/iotex-core/bin/addrgen /usr/local/bin/iotex-addrgen && \
+    cp $GOPATH/src/github.com/iotexproject/iotex-core/bin/ioctl /usr/local/bin/ioctl && \
     cp ./crypto/lib/libsect283k1_ubuntu.so /usr/lib/ && \
     cp ./crypto/lib/blslib/libtblsmnt_ubuntu.so /usr/lib/ && \
     mkdir -p /etc/iotex/ && \