Fix to enable running CI jobs locally

Summary:
We may not have permission on all /dev/shm to fix the sticky bit.
Making the sticky bit fix advisory.

Test Plan: Run CI job locally

Subscribers: andrewkr, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D61371

build_tools/rocksdb-lego-determinator

@@ -59,7 +59,7 @@ fi
 CLEANUP_ENV="
 {
     'name':'Cleanup environment',
-    'shell':'rm -rf /dev/shm/rocksdb && mkdir /dev/shm/rocksdb && chmod +t /dev/shm && make clean',
+    'shell':'rm -rf /dev/shm/rocksdb && mkdir /dev/shm/rocksdb && (chmod +t /dev/shm || true)  && make clean',
     'user':'root'
 }"