Remove old unused cache and nvm_cache files and the nvml dependency

Summary:
Remove old unused cache and nvm_cache files and the nvml dependency.

Also add a patch for boost to get rid of compile-time warnings
(boostorg/random#49, patch taken from
toonetown/boostorg-boost@457767e).

Also when checking Python syntax don't fail when a file does not exist. This could happen when
removing a file (in this case, nvml.py) and using remote_build.py, because remote_build.py
relies on `git ls-files`.

Test Plan: Jenkins

Reviewers: sergei

Reviewed By: sergei

Subscribers: ybase

Differential Revision: https://phabricator.dev.yugabyte.com/D5974

.arclint

@@ -17,7 +17,8 @@
         "(^cmake_modules/cotire[.]cmake$)",
         "(^cmake_modules/FindBoost[.]cmake$)",
         "(^README[.]md$)",
-        "(^java/pom[.]xml$)"
+        "(^java/pom[.]xml$)",
+        "(^.*[.]patch$)"
       ]
     },
     "pycodestyle": {

build-support/check_python_syntax.py

@@ -28,7 +28,9 @@ def horizontal_line():
     filename = sys.argv[1]
     if not os.path.exists(filename):
         print >>sys.stderr, "Python file does not exist, cannot check syntax: %s" % filename
-        sys.exit(1)
+        print >>sys.stderr, "This file might have been deleted as part of the latest commit."
+        # Don't consider this an error.
+        sys.exit(0)
 
     source = open(filename, 'r').read() + '\n'
     try:

src/yb/util/CMakeLists.txt

@@ -133,7 +133,6 @@ set(UTIL_SRCS
   bitmap.cc
   bloom_filter.cc
   bytes_formatter.cc
-  cache.cc
   cache_metrics.cc
   coding.cc
   concurrent_value.cc
@@ -232,12 +231,6 @@ set(UTIL_SRCS
   ${UTIL_SRCS_EXTENSIONS}
   )
 
-if(NOT APPLE)
-  set(UTIL_SRCS
-    ${UTIL_SRCS}
-    nvm_cache.cc)
-endif()
-
 set(UTIL_LIBS
   boost_system
   boost_thread
@@ -325,7 +318,6 @@ ADD_YB_TEST(bit-util-test)
 ADD_YB_TEST(bitmap-test)
 ADD_YB_TEST(blocking_queue-test)
 ADD_YB_TEST(bloom_filter-test)
-ADD_YB_TEST(cache-test)
 ADD_YB_TEST(callback_bind-test)
 ADD_YB_TEST(countdown_latch-test)
 ADD_YB_TEST(crc-test RUN_SERIAL true) # has a benchmark