Packaging now uses gvm

This allows the script to set the exact version of Go used to build the
program.

package.sh

@@ -49,6 +49,7 @@ MAINTAINER=support@influxdb.com
 VENDOR=Influxdb
 DESCRIPTION="Distributed time-series database"
 
+GO_VERSION="1.4.2"
 GOPATH_INSTALL=
 BINS=(
     influxd
@@ -82,6 +83,19 @@ check_gopath() {
     echo "GOPATH ($GOPATH) looks sane, using $GOPATH_INSTALL for installation."
 }
 
+check_gvm() {
+    which gvm
+    if [ $? -ne 0 ]; then
+        echo "gvm not found -- aborting."
+        cleanup_exit $1
+    fi
+    gvm use $GO_VERSION
+    if [ $? -ne 0]; then
+        echo "gvm cannot find Go version $GO_VERSION -- aborting."
+        cleanup_exit $1
+    fi
+}
+
 # check_clean_tree ensures that no source file is locally modified.
 check_clean_tree() {
     modified=$(git ls-files --modified | wc -l)
@@ -207,6 +221,7 @@ fi
 
 echo -e "\nStarting package process...\n"
 
+check_gvm
 check_gopath
 check_clean_tree
 update_tree