THRIFT-4423: migrate to psr-4
Client: php

This closes #1445
diff --git a/build/docker/ubuntu-trusty/Dockerfile b/build/docker/ubuntu-trusty/Dockerfile
index db2041a..394e84f 100644
--- a/build/docker/ubuntu-trusty/Dockerfile
+++ b/build/docker/ubuntu-trusty/Dockerfile
@@ -25,8 +25,8 @@
 MAINTAINER Apache Thrift <dev@thrift.apache.org>
 ENV DEBIAN_FRONTEND noninteractive
 
-RUN apt-get update && \ 
-    apt-get dist-upgrade -y && \ 
+RUN apt-get update && \
+    apt-get dist-upgrade -y && \
     apt-get install -y --no-install-recommends \
       apt \
       apt-transport-https \
@@ -166,8 +166,8 @@
       php5-cli \
       php5-dev \
       php-pear \
-      re2c \
-      phpunit
+      re2c && \
+      wget https://getcomposer.org/installer -O - -q | php -- --quiet --install-dir=/usr/local/bin/ --filename=composer
 
 RUN apt-get install -y --no-install-recommends \
 `# Python dependencies` \
@@ -189,7 +189,7 @@
       python3-wheel \
       python3-zope.interface && \
     pip install -U ipaddress backports.ssl_match_hostname tornado && \
-    pip3 install -U backports.ssl_match_hostname tornado 
+    pip3 install -U backports.ssl_match_hostname tornado
 # installing tornado by pip/pip3 instead of debian package
 # if we install the debian package, the build fails in py2