vendor.sh can cleanly update vendored dependencies

vendor.sh → hack/vendor.sh

@@ -9,9 +9,14 @@ vendor_dir=${PWD}/vendor
 git_clone () {
   PKG=$1
   REV=$2
-  if [[ ! -d src/$PKG ]]; then
-    cd $vendor_dir && git clone http://$PKG src/$PKG && cd src/$PKG && git checkout -f $REV
-  fi
+  (
+    set -e
+    cd $vendor_dir
+    if [[ ! -d src/$PKG ]]; then
+      cd $vendor_dir && git clone http://$PKG src/$PKG
+    fi
+    cd src/$PKG && git checkout -f $REV
+  )
 }
 
 git_clone github.com/kr/pty 27435c699
@@ -24,6 +29,11 @@ git_clone github.com/dotcloud/tar/ d06045a6d9
 
 # Docker requires code.google.com/p/go.net/websocket
 PKG=code.google.com/p/go.net REV=84a4013f96e0
-if [[ ! -d src/$PKG ]]; then
-  cd $vendor_dir && hg clone https://$PKG src/$PKG && cd src/$PKG && hg checkout -r $REV
-fi
+(
+  set -e
+  cd $vendor_dir
+  if [[ ! -d src/$PKG ]]; then
+    hg clone https://$PKG src/$PKG
+  fi
+  cd src/$PKG && hg checkout -r $REV
+)