Fix uninitialized variable added in b33b9a6

After discussing with BlueMatt, this appears to be harmless in its
current state since it's always set before it's used. Initialize it
anyway for readability and future safety.

Author: theuni

src/main.h

@@ -937,7 +937,7 @@ class CValidationState {
     unsigned char chRejectCode;
     bool corruptionPossible;
 public:
-    CValidationState() : mode(MODE_VALID), nDoS(0) {}
+    CValidationState() : mode(MODE_VALID), nDoS(0), corruptionPossible(false) {}
     bool DoS(int level, bool ret = false,
              unsigned char chRejectCodeIn=0, std::string strRejectReasonIn="",
              bool corruptionIn=false) {