update_bootstrap.sh in less-rails-bootstrap-3.0.4

- old
+ new

@@ -36,9 +36,14 @@
 fi
 
 if [ ! -d $bs_dir ]; then
     info "Bootstrap not found. Cloning to twitter/bootstrap..."
     git clone --quiet git://github.com/twbs/bootstrap.git twitter/bootstrap
+else
+    info "Bootstrap found. Fetching to twitter/bootstrap..."
+    cd $bs_dir
+    git fetch
+    cd - > /dev/null
 fi
 
 cd twitter/bootstrap
 info "Using $1..."
 git checkout --quiet $1