[validation] Replace tx index code in validation code with TxIndex.

src/init.cpp

@@ -1483,12 +1483,6 @@ bool AppInitMain()
                     return InitError(_("Incorrect or no genesis block found. Wrong datadir for network?"));
                 }
 
-                // Check for changed -txindex state
-                if (fTxIndex != gArgs.GetBoolArg("-txindex", DEFAULT_TXINDEX)) {
-                    strLoadError = _("You need to rebuild the database using -reindex to change -txindex");
-                    break;
-                }
-
                 // Check for changed -prune state.  What we are concerned about is a user who has pruned blocks
                 // in the past, but is now trying to run unpruned.
                 if (fHavePruned && !fPruneMode) {