Bug 1458627 - Bump MODERN_MERCURIAL_VERSION to 4.3.3; r=sheehan

We bump the Mercurial version after a new Mercurial release. 4.6 was
just released. So...

MozReview-Commit-ID: LQ49eVCDuGG

--HG--
extra : rebase_source : 6b213a62216d1b8a9ec4f303d05d01e0609734a1

python/mozboot/mozboot/base.py

@@ -144,7 +144,7 @@ ac_add_options --enable-artifact-builds
 # Upgrade Mercurial older than this.
 # This should match OLDEST_NON_LEGACY_VERSION from
 # the hg setup wizard in version-control-tools.
-MODERN_MERCURIAL_VERSION = LooseVersion('4.2.3')
+MODERN_MERCURIAL_VERSION = LooseVersion('4.3.3')
 
 # Upgrade Python older than this.
 MODERN_PYTHON_VERSION = LooseVersion('2.7.3')