Fix clang-tidy errors from switching to C++17

Disable clang-tidy checks that enforce coding patterns specific to C++17
until the codebase can be updated.

Change-Id: Ic720dec6720b325b1f19d3c2e4c31f4a8e081a01

.clang-tidy

@@ -37,7 +37,6 @@ Checks: >
   -misc-unconventional-assign-operator,
   -misc-unused-parameters,
   modernize-avoid-bind,
-  modernize-concat-nested-namespaces,
   modernize-deprecated-ios-base-aliases,
   modernize-make-shared,
   modernize-replace-auto-ptr,
@@ -46,7 +45,6 @@ Checks: >
   modernize-shrink-to-fit,
   modernize-unary-static-assert,
   modernize-use-bool-literals,
-  modernize-use-nodiscard,
   modernize-use-noexcept,
   modernize-use-transparent-functors,
   modernize-use-uncaught-exceptions,