Add special handling for node v0.6.21-pre

nvm.sh

@@ -205,7 +205,13 @@ nvm_ls_current() {
   if [ $? -ne 0 ]; then
     echo 'none'
   elif nvm_tree_contains_path "$NVM_DIR" "$NODE_PATH"; then
-    echo `node -v 2>/dev/null`
+    local VERSION
+    VERSION=`node -v 2>/dev/null`
+    if [ "$VERSION" = "v0.6.21-pre" ]; then
+      echo "v0.6.21"
+    else
+      echo "$VERSION"
+    fi
   else
     echo 'system'
   fi

test/slow/Running "nvm current" should display current nvm environment.

@@ -8,3 +8,7 @@ nvm install 0.10
 
 [ "$(nvm current)" = "$(node -v)" ] || die "Failed to find current version: got \"$(nvm current)\", expected \"$(node -v)\""
 
+nvm install 0.6.21
+[ "$(node -v)" = "v0.6.21-pre" ] || die "v0.6.21-pre not installed with v0.6.21"
+[ "$(nvm current)" = "v0.6.21" ] || die "v0.6.21-pre not reported as v0.6.21"
+