Remove P2SH coinbase flag, no longer interesting

Github-Pull: #6203
Rebased-From: d449772cf69c01932fc5d72c46054815d6300b3c

src/init.cpp

@@ -787,12 +787,6 @@ bool AppInit2(boost::thread_group& threadGroup, CScheduler& scheduler)
     if (nConnectTimeout <= 0)
         nConnectTimeout = DEFAULT_CONNECT_TIMEOUT;
 
-    // Continue to put "/P2SH/" in the coinbase to monitor
-    // BIP16 support.
-    // This can be removed eventually...
-    const char* pszP2SH = "/P2SH/";
-    COINBASE_FLAGS << std::vector<unsigned char>(pszP2SH, pszP2SH+strlen(pszP2SH));
-
     // Fee-per-kilobyte amount considered the same as "free"
     // If you are mining, be careful setting this:
     // if you set it to zero then