Fix hostname detection

build.sh

@@ -3,12 +3,17 @@
 
 
 workspace=$1
-hostname=$(cat hostname)
 target=$3
 comp_type=$4
 branch=$5
 with_gpu=$6
 
+if [ -f hostname ]; then
+   hostname=$(cat hostname)
+else
+   hostname=$(hostname)
+fi
+
 if [ x"$branch" == x"" ]; then
   echo "Getting branch from git"
   branch=$(git ls-remote --heads origin | grep $(git rev-parse HEAD) | cut -d / -f 3)