MUSIC: add samtools to the Dockerfile

src/docker_modules/MUSIC/6613c53/Dockerfile

-FROM ubuntu:18.04
+FROM samtools:1.7
 MAINTAINER Laurent Modolo
 
 ENV PACKAGES git=1:2.17* \
@@ -21,3 +21,5 @@ RUN git clone https://github.com/gersteinlab/MUSIC.git && \
   mv MUSIC/bin/run_MUSIC.csh /usr/bin/ && \
   rm -Rf MUSIC
 
+RUN chmod +x /usr/bin/*
+