go: change default version and clean image

go/Dockerfile

@@ -5,4 +5,10 @@
 FROM tsuru/base-platform
 ADD	. /var/lib/tsuru/go
 RUN	cp /var/lib/tsuru/go/deploy /var/lib/tsuru
-RUN	/var/lib/tsuru/go/install
+RUN set -ex; \
+    apt-get update && \
+    apt-get install -y bzr mercurial git && \
+    /var/lib/tsuru/go/install && \
+    rm -rf /var/lib/apt/lists/* && \
+    apt-get autoremove -y && \
+    apt-get clean

go/deploy

@@ -8,8 +8,10 @@ SOURCE_DIR=/var/lib/tsuru
 source ${SOURCE_DIR}/base/deploy
 source ${SOURCE_DIR}/base/rc/config
 
-GO_VERSION=$(test -f /tmp/app_envs && source /tmp/app_envs && echo $GO_VERSION)
-GO_VERSION=${GO_VERSION:-1.7.4}
+go_default_version="stable"
+if [ -z "${GO_VERSION}" ]; then
+  GO_VERSION="${go_default_version}"
+fi
 echo "Installing Go ${GO_VERSION}..."
 eval "$(gimme ${GO_VERSION})" >/dev/null 2>&1
 
@@ -19,7 +21,7 @@ fi
 
 APP_PATH=${APP_DIR}/src/current
 
-if [ ! -z "${GO_PKG_PATH}" ]
+if [ -n  "${GO_PKG_PATH}" ]
 then
 	APP_PATH=${APP_DIR}/src/${GO_PKG_PATH}
 fi

go/install

@@ -10,7 +10,7 @@ source ${SOURCE_DIR}/base/rc/config
 
 curl -sL https://raw.githubusercontent.com/travis-ci/gimme/master/gimme -o /usr/bin/gimme
 chmod +x /usr/bin/gimme
-apt-get update && apt-get install bzr mercurial git -y
+
 cp ${SOURCE_DIR}/go/Procfile ${SOURCE_DIR}/default/Procfile
 echo "GOPATH=${APP_DIR}" >> ${HOME}/.profile
 echo 'PATH=$GOPATH:$PATH' >> ${HOME}/.profile
@@ -19,7 +19,7 @@ echo 'export GIMME_SILENT_ENV=1' >> ${HOME}/.profile
 echo '[ -f ${HOME}/.gimme/envs/latest.env ] && source ${HOME}/.gimme/envs/latest.env' >> ${HOME}/.profile
 
 sudo -u ubuntu mkdir -p ${HOME}/.gimme/versions
-GO_VERSIONS="1.7.6 1.8.3 stable"
+GO_VERSIONS="stable"
 for GO_VERSION in ${GO_VERSIONS}
 do
     echo "Installing Go ${GO_VERSION}..."