Leave shell default

Dockerfile

@@ -7,7 +7,7 @@ RUN apt-get update \
  && apt-get install -y openssh-server \
  && rm -f /etc/ssh/ssh_host_* \
  && groupadd --non-unique --gid $GROUPID data \
- && useradd --non-unique --uid $USERID --gid $GROUPID --no-create-home --home-dir $DATADIR --shell /usr/bin/rssh $OWNER \
+ && useradd --non-unique --uid $USERID --gid $GROUPID --no-create-home --home-dir $DATADIR $OWNER \
  && mkdir -p "$DATADIR" \
  && chown $OWNER "$DATADIR" \
  && echo "AuthorizedKeysFile $AUTHORIZED_KEYS_FILE" >>/etc/ssh/sshd_config \