Re-add back root Dockerfile for cross comiling and with GOPATH setup correctly.

Fix notary-server Dockerfile so the COPY is after the run otherwise the cache
will bust on the COPY and you wind up having to run the RUN apt-get every
single time you build the Dockerfile.

Signed-off-by: Jessica Frazelle <princess@docker.com>

Dockerfile

@@ -0,0 +1,14 @@
+FROM golang:1.4.2-cross
+
+RUN apt-get update && apt-get install -y \
+    libltdl-dev \
+	--no-install-recommends \
+	&& rm -rf /var/lib/apt/lists/*
+
+RUN go get golang.org/x/tools/cmd/vet
+
+COPY . /go/src/github.com/docker/notary
+
+ENV GOPATH /go/src/github.com/docker/notary/Godeps/_workspace:$GOPATH
+
+WORKDIR /go/src/github.com/docker/notary

notary-server-Dockerfile

@@ -1,9 +1,11 @@
 FROM golang
 
-COPY . /go/src/github.com/docker/notary
-
 RUN apt-get update && apt-get install -y \
-    libltdl-dev
+    libltdl-dev \
+	--no-install-recommends \
+	&& rm -rf /var/lib/apt/lists/*
+
+COPY . /go/src/github.com/docker/notary
 
 ENV GOPATH /go/src/github.com/docker/notary/Godeps/_workspace:$GOPATH
 

notary-signer-Dockerfile

@@ -8,9 +8,23 @@ ENV SOPIN="1234"
 ENV LIBDIR="/usr/local/lib/softhsm/"
 
 # Install openSC and dependencies
-RUN apt-get update
-
-RUN apt-get install -y build-essential autoconf automake libtool gtk-doc-tools gengetopt help2man libpcsclite-dev libzip-dev opensc libssl-dev usbutils vim
+RUN apt-get update && \
+	apt-get install -y \
+	build-essential \
+	autoconf \
+	automake \
+	libtool \
+	gtk-doc-tools \
+	gengetopt \
+	help2man \
+	libpcsclite-dev \
+	libzip-dev \
+	opensc \
+	libssl-dev \
+	usbutils \
+	vim \
+	--no-install-recommends \
+	&& rm -rf /var/lib/apt/lists/*
 
 # Initialize the SoftHSM2 token on slod 0, using PIN and SOPIN varaibles
 RUN softhsm2-util --init-token --slot 0 --label "test_token" --pin $PIN --so-pin $SOPIN