Use latest edx-lint. Adds getattr/setattr string literal checking.

There are 80 of these new violations in the tree, so up the lint
threshold also.

requirements/edx/github.txt

@@ -50,7 +50,7 @@ git+https://github.com/edx/edx-oauth2-provider.git@0.5.6#egg=oauth2-provider==0.
 -e git+https://github.com/pmitros/RecommenderXBlock.git@518234bc354edbfc2651b9e534ddb54f96080779#egg=recommender-xblock
 -e git+https://github.com/edx/edx-search.git@release-2015-07-22#egg=edx-search
 -e git+https://github.com/edx/edx-milestones.git@release-2015-06-17#egg=edx-milestones
-git+https://github.com/edx/edx-lint.git@ed8c8d2a0267d4d42f43642d193e25f8bd575d9b#egg=edx_lint==0.2.3
+git+https://github.com/edx/edx-lint.git@b109a40c61277c52dcb396bf15e33755f5dbf5fa#egg=edx_lint==0.2.4
 -e git+https://github.com/edx/xblock-utils.git@213a97a50276d6a2504d8133650b2930ead357a0#egg=xblock-utils
 -e git+https://github.com/edx-solutions/xblock-google-drive.git@138e6fa0bf3a2013e904a085b9fed77dab7f3f21#egg=xblock-google-drive
 -e git+https://github.com/edx/edx-reverification-block.git@1e8f5a7fd589951a90bd31a0824a2c01ac9598ce#egg=edx-reverification-block

scripts/all-tests.sh

@@ -11,7 +11,7 @@ set -e
 ###############################################################################
 
 # Violations thresholds for failing the build
-export PYLINT_THRESHOLD=6200
+export PYLINT_THRESHOLD=6275
 export JSHINT_THRESHOLD=3700
 
 doCheckVars() {