Merge pull request #312 from quiqueg/master

Fixed bash error caused by lack of double quotes

nvm.sh

@@ -389,7 +389,7 @@ nvm() {
       if [ -z $VERSION ]; then
         VERSION=`nvm_version $2`
       fi
-      if [ ! -d $NVM_DIR/$VERSION ]; then
+      if [ ! -d "$NVM_DIR/$VERSION" ]; then
         echo "$VERSION version is not installed yet"
         return 1
       fi