ERP5: remove useless version pinning on mysqlclient

stack/erp5/buildout.cfg

@@ -621,7 +621,7 @@ scripts +=
 
 [versions]
 # See ../../software/neoppod/software-common.cfg for versions common with NEO:
-#  neoppod, python-mysqlclient, slapos.recipe.template & [slapos-deps-eggs]
+#  neoppod, mysqlclient, slapos.recipe.template & [slapos-deps-eggs]
 
 # patched eggs
 Acquisition = 2.13.9+SlapOSPatched001
@@ -706,7 +706,6 @@ ipywidgets = 4.1.1
 logilab-common = 1.2.0
 matplotlib = 1.5.1
 mistune = 0.7.2
-mysqlclient = 1.3.7
 numpy = 1.11.0
 objgraph = 2.0.1
 pandas = 0.18.0