Use rust 1.41 and builtin rockdb

Author: Aleksei Sidorov

.travis.yml

@@ -35,7 +35,7 @@ addons:
 
 env:
   global:
-    - RUST_COMPILER_VERSION=1.36.0
+    - RUST_COMPILER_VERSION=1.41.0
     - ROCKSDB_LIB_DIR=/usr/lib
     # REPO_TOKEN used for integration with coveralls is encoded here
     - secure: 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
@@ -60,10 +60,6 @@ matrix:
       osx_image: xcode11.3
       env:
         - CHECK_RUST=false
-        - ROCKSDB_LIB_DIR=/usr/local/lib
-        - ROCKSDB_STATIC=1
-        - SNAPPY_LIB_DIR=/usr/local/lib
-        - SNAPPY_STATIC=1
 
 cache:
   directories: