Revert "add /.nvm to NVM_DIR so we dont clutter up home directories"

This reverts commit a107b12d2a.

nvm.sh

@@ -7,7 +7,7 @@
 
 # Auto detect the NVM_DIR
 if [ ! -d "$NVM_DIR" ]; then
-    export NVM_DIR=$(cd $(dirname ${BASH_SOURCE[0]:-$0}) && pwd)'/.nvm'
+    export NVM_DIR=$(cd $(dirname ${BASH_SOURCE[0]:-$0}) && pwd)
 fi
 
 # Make zsh glob matching behave same as bash