nvm_install_latest_npm: npm v5.4+ breaks on node v4-4.4 and v5-5.9,…

… due to missing `Buffer.alloc`.

nvm.sh

@@ -206,8 +206,16 @@ nvm_install_latest_npm() {
     nvm_echo '* `npm` v5 and higher do not work on `node` versions below v4.0.0'
     $NVM_NPM_CMD install -g npm@4
   elif [ $NVM_IS_0_9 -eq 0 ] && [ $NVM_IS_0_6 -eq 0 ]; then
-    nvm_echo '* Installing latest `npm`; if this does not work on your node version, please report a bug!'
-    $NVM_NPM_CMD install -g npm
+    if nvm_version_greater 4.5.0 "${NODE_VERSION}" || (\
+      nvm_version_greater_than_or_equal_to "${NODE_VERSION}" 5.0.0 \
+      && nvm_version_greater 5.10.0 "${NODE_VERSION}"\
+    ); then
+      nvm_echo '* `npm` `v5.3.x` is the last version that works on `node` 4.x versions below v4.4, or 5.x versions below v5.10, due to `Buffer.alloc`'
+      $NVM_NPM_CMD install -g [email protected]
+    else
+      nvm_echo '* Installing latest `npm`; if this does not work on your node version, please report a bug!'
+      $NVM_NPM_CMD install -g npm
+    fi
   fi
   nvm_echo "* npm upgraded to: v$(npm --version 2>/dev/null)"
 }