fix boolean check for unknown rtconf variables in files.

src/utils/SkRTConf.cpp

Index: src/utils/SkRTConf.cpp
diff --git a/src/utils/SkRTConf.cpp b/src/utils/SkRTConf.cpp
index 29f0238dd86f110f04c0fc90ed800501db4721a4..bc2031f2e847ee001a6a44509feb3189d5fdd55e 100644
--- a/src/utils/SkRTConf.cpp
+++ b/src/utils/SkRTConf.cpp
@@ -76,7 +76,7 @@ void SkRTConfRegistry::possiblyDumpFile() const {
 // declared a correponding configuration object somewhere.
 void SkRTConfRegistry::validate() const {
     for (int i = 0 ; i < fConfigFileKeys.count() ; i++) {
-        if (fConfs.find(fConfigFileKeys[i]->c_str())) {
+        if (!fConfs.find(fConfigFileKeys[i]->c_str())) {
             SkDebugf("WARNING: You have config value %s in your configuration file, but I've never heard of that.\n", fConfigFileKeys[i]->c_str());
         }
     }