Bug 1542376 - Avoid exception during Android bootstrap. r=glandium

Mozboot uses Python 2.7.3, along with the |unicode_literals| directive,
which makes string literals unicode by default. However, the
LooseVersion implementation that ships with Python throws an exception
when comparing against bare unicode strings, because it only checks for
StringType, not UnicodeType [1].

[1] https://github.com/enthought/Python-2.7.3/blob/master/Lib/distutils/version.py#L292

Differential Revision: https://phabricator.services.mozilla.com/D26378

python/mozboot/mozboot/base.py

@@ -708,7 +708,7 @@ class BaseBootstrapper(object):
 
         if 'mobile_android' in self.application:
             # Let's add the most common targets.
-            if rust_version < '1.33':
+            if rust_version < LooseVersion('1.33'):
                 arm_target = 'armv7-linux-androideabi'
             else:
                 arm_target = 'thumbv7neon-linux-androideabi'