increase RAM and CPU cores for Vagrant template

reduce RAM for Vagrant VMs used to run tests

build packages with multiple threads

refs #4382

Change-Id: I30ad59a6e705bafa60f5680f725b528bac5f9833
diff --git a/install_helpers/install_NFD.py b/install_helpers/install_NFD.py
index 830644d..748af57 100644
--- a/install_helpers/install_NFD.py
+++ b/install_helpers/install_NFD.py
@@ -7,10 +7,9 @@
     print "**************"
     os.system("git clone --depth 1 https://github.com/named-data/NFD")
     os.chdir("NFD")
-    os.system("./waf distclean")
     os.system("git submodule init && git submodule update")
     os.system("./waf configure")
-    os.system("./waf -j1")
+    os.system("./waf")
     os.system("sudo ./waf install")
     os.system("sudo cp /usr/local/etc/ndn/nfd.conf.sample /usr/local/etc/ndn/nfd.conf")
     os.system("sudo mkdir /usr/local/etc/ndn/keys/")