Merge pull request #2705 from robbak/crash_zero_size_peers.dat

Don't attempt to resize vector to negative size.

src/db.cpp

@@ -541,6 +541,8 @@ bool CAddrDB::Read(CAddrMan& addr)
     // use file size to size memory buffer
     int fileSize = GetFilesize(filein);
     int dataSize = fileSize - sizeof(uint256);
+    //Don't try to resize to a negative number if file is small
+    if ( dataSize < 0 ) dataSize = 0;
     vector<unsigned char> vchData;
     vchData.resize(dataSize);
     uint256 hashIn;