Bug 1556257 - Add Funtoo support to mach bootstrap. r=froydnj

Differential Revision: https://phabricator.services.mozilla.com/D33425

--HG--
extra : moz-landing-system : lando

python/mozboot/mozboot/bootstrap.py

@@ -249,7 +249,7 @@ class Bootstrapper(object):
             elif distro in DEBIAN_DISTROS:
                 cls = DebianBootstrapper
                 args['distro'] = distro
-            elif distro == 'Gentoo Base System':
+            elif distro in ('Gentoo Base System', 'Funtoo Linux - baselayout '):
                 cls = GentooBootstrapper
             elif os.path.exists('/etc/arch-release'):
                 # Even on archlinux, platform.linux_distribution() returns ['','','']