Remove shfmt

We don't have that many scripts and for the amount of errors this is
causing on a weekly basis for contributors its not worth the overhead.

Signed-off-by: Michael Crosby <crosbymichael@gmail.com>

Dockerfile

@@ -47,15 +47,6 @@ RUN mkdir -p /usr/src/criu \
     && make install-criu \
     && rm -rf /usr/src/criu
 
-# install shfmt
-RUN mkdir -p /go/src/github.com/mvdan \
-    && cd /go/src/github.com/mvdan \
-    && git clone https://github.com/mvdan/sh \
-    && cd sh \
-    && git checkout -f v0.4.0 \
-    && go install ./cmd/shfmt \
-    && rm -rf /go/src/github.com/mvdan
-
 # setup a playground for us to spawn containers in
 ENV ROOTFS /busybox
 RUN mkdir -p ${ROOTFS} \