msfconsole boots agains

MSP-8891 #finish

msfconsole did not boot because lib/rex/constants.rb did not have
metasploit/model loaded prior to defining the ARCH constants and the
driver could not startup because it was referring to an obsolete method
on the module manager.
Merge branch 'bug/metasploit-framework-module-cache-prefetch-time' into bug/msfconsole-boot
Merge branch 'feature/module-cache-construction' into bug/msfconsole-boot
Land limhoff-r7/metasploit-framework#9

Should save msfconsole now.