message: Fix binary WASM detection in eosioc
  Fix using a binary wasm for set constract. This check got goofed up. Fixes issue reported in
diff: @@ -639,7 +639,7 @@ int main( int argc, char** argv ) {
  fc::read_file_contents(wastPath, wast);
  vector<uint8_t> wasm;
  - const string binary_wasm_header = "\x00\x61\x73\x6d";
  + const string binary_wasm_header("\x00\x61\x73\x6d", 4);
  if(wast.compare(0, 4, binary_wasm_header) == 0) {
  std::cout << localized("Using already assembled WASM...") << std::endl;
  wasm = vector<uint8_t>(wast.begin(), wast.end());
  