Modify DISALLOW_COPY_AND_ASSIGN to delete instead of relying on visibility

By deleting the functions instead of just declaring them it becomes
harder to use the macros wrong. It also means more meaningful compiler
errors are generated if someone tries to use the deleted functions.

This also removes an unused private variable that can now be statically
proven by the compiler as unused (and therefore generates a warning).

Change-Id: I13c7a04a8e56bc62a5a6b9f765889e88428a7388
Reviewed-on: http://review.couchbase.org/70587
Tested-by: buildbot <build@couchbase.com>
Reviewed-by: Daniel Owen <owend@couchbase.com>
Reviewed-by: Dave Rigby <daver@couchbase.com>

Author: Chippiewill

src/flusher.h

@@ -125,7 +125,6 @@ class Flusher {
     double                   minSleepTime;
     uint16_t                 initCommitInterval;
     uint16_t                 currCommitInterval;
-    rel_time_t               flushStart;
     std::atomic<bool> forceShutdownReceived;
     std::queue<uint16_t> hpVbs;
     std::queue<uint16_t> lpVbs;

src/utility.h

@@ -31,15 +31,13 @@
 
 #include <memcached/extension.h>
 
-// Stolen from http://google-styleguide.googlecode.com/svn/trunk/cppguide.xml
 // A macro to disallow the copy constructor and operator= functions
-// This should be used in the private: declarations for a class
 #define DISALLOW_COPY_AND_ASSIGN(TypeName)      \
-    TypeName(const TypeName&);                  \
-    void operator=(const TypeName&)
+    TypeName(const TypeName&) = delete;         \
+    void operator=(const TypeName&) = delete
 
 #define DISALLOW_ASSIGN(TypeName)               \
-    void operator=(const TypeName&)
+    void operator=(const TypeName&) = delete
 
 
 // Utility functions implemented in various modules.