Update Rspec expected thread count

When REMOTE_DB is set there is a thread for the web service, in
addition to the External modules thread manager, so there is one or two
threads by the end of the test run in addition to the main VM thread.

lib/metasploit/framework/spec/threads/suite.rb

@@ -12,7 +12,7 @@ module Metasploit
           #
 
           # Number of allowed threads when threads are counted in `after(:suite)` or `before(:suite)`
-          EXPECTED_THREAD_COUNT_AROUND_SUITE = 2
+          EXPECTED_THREAD_COUNT_AROUND_SUITE = ENV['REMOTE_DB'] ? 3 : 2
 
           # `caller` for all Thread.new calls
           LOG_PATHNAME = Pathname.new('log/metasploit/framework/spec/threads/suite.log')