epicsTime: rely on implicit copy constructor

When a custom copy constructor is defined the assignment operator
also needs to be defined explicitly. For this simple class the
implicit copy ctor/assignment operator are sufficient, though. This
fixes a warning emitted by GCC9.

src/libCom/osi/epicsTime.cpp

@@ -205,9 +205,6 @@ epicsTime::epicsTime (const epicsTimeStamp &ts)
 epicsTime::epicsTime () :
     secPastEpoch(0u), nSec(0u) {}
 
-epicsTime::epicsTime (const epicsTime &t) :
-    secPastEpoch (t.secPastEpoch), nSec (t.nSec) {}
-
 epicsTime epicsTime::getCurrent ()
 {
     epicsTimeStamp current;

src/libCom/osi/epicsTime.h

@@ -81,7 +81,6 @@ public:
     class formatProblemWithStructTM {};
 
     epicsTime ();
-    epicsTime ( const epicsTime & t );
 
     static epicsTime getEvent ( const epicsTimeEvent & );
     static epicsTime getCurrent ();