Delete dangerous comparison operators from base::expected

These operators were included because they're present in the draft
standard proposal of std::expected, but they were deemed to lead to
bugs, particularly when T is implicitly convertible to bool.

Change-Id: Ib149decf1f230198f358dc1ae0eaed71961363f6
Test: m
diff --git a/init/service_parser.cpp b/init/service_parser.cpp
index 1d431e3..3f81792 100644
--- a/init/service_parser.cpp
+++ b/init/service_parser.cpp
@@ -208,7 +208,7 @@
 
         // If the property is not set, it defaults to none, in which case there are no keycodes
         // for this service.
-        if (expanded == "none") {
+        if (*expanded == "none") {
             return {};
         }