fix compiler warning

Author: brianc

package.json

@@ -1,5 +1,5 @@
 { "name": "pg",
-  "version": "0.6.0",
+  "version": "0.6.1",
   "description": "PostgreSQL client - pure javascript & libpq with the same API",
   "keywords" : ["postgres", "pg", "libpq", "postgre", "database", "rdbms"],
   "homepage": "http://github.com/brianc/node-postgres",

src/binding.cc

@@ -497,13 +497,13 @@ class Connection : public ObjectWrap {
 
 private:
   //EventEmitter was removed from c++ in node v0.5.x
-  void Emit(char* message) {
+  void Emit(const char* message) {
     HandleScope scope;
     Handle<Value> args[1] = { String::New(message) };
     Emit(1, args);
   }
 
-  void Emit(char* message, Handle<Value>* arg) {
+  void Emit(const char* message, Handle<Value>* arg) {
     HandleScope scope;
     Handle<Value> args[2] = { String::New(message), *arg };
     Emit(2, args);