remove useless debian package in kerberos image

.docker/build/kerberos/Dockerfile

@@ -8,9 +8,6 @@ RUN { \
     } | debconf-set-selections \
     && \
     apt-get update && apt-get install -y --no-install-recommends \
-        build-essential \
-        gcc \
-        apt-utils \
         krb5-user \
         krb5-config \
         openssh-client \