Reorder nvm install commands to remove confusing messages

The program nvm is now reporting that "N/A version is not installed" when
sourcing the nvm script. Reorder the nvm installation commands that this
message only occurs once during the install of node (which is before any
node version is installed) so there is less confusion.

OSEHRA-Id: http://issues.osehra.org/browse/VAF-186
Change-Id: I899af30b7062e3036b073e0f9b0caf0571044614
Merge "Reorder nvm install commands to remove confusing messages"