Clean up warnings

Removed unused member variables 'bool dim'.

src/pv/ntcontinuum.h

@@ -93,7 +93,6 @@ namespace detail {
 
         void reset();
 
-        bool dim;
         bool descriptor;
         bool alarm;
         bool timeStamp;

src/pv/nthistogram.h

@@ -103,7 +103,6 @@ namespace detail {
         bool valueTypeSet;
         epics::pvData::ScalarType valueType;
 
-        bool dim;
         bool descriptor;
         bool alarm;
         bool timeStamp;