crew: do not exclude .git when caching git dirs

bin/crew

@@ -786,7 +786,9 @@ def download
       if CREW_CACHE_ENABLED and File.writable?(CREW_CACHE_DIR)
         puts 'Caching downloaded git repo...'
         Dir.chdir "#{@extract_dir}" do
-          system "tar c#{@verbose}Jf #{cachefile} --exclude-vcs \
+          # Do not use --exclude-vcs to exclude .git
+          # because some builds will use that information.
+          system "tar c#{@verbose}Jf #{cachefile} \
             $(find -mindepth 1 -maxdepth 1 -printf '%P\n')"
         end
         system "sha256sum #{cachefile} > #{cachefile}.sha256"