Fix string.compare() logic.  It happens to be working luckily.

Change-Id: I262c6d5779124e5b09ad1a66ca3c9ddb2fc6d7d5
diff --git a/native/jni/src/additional_proximity_chars.h b/native/jni/src/additional_proximity_chars.h
index ba76cfc..c22de7d 100644
--- a/native/jni/src/additional_proximity_chars.h
+++ b/native/jni/src/additional_proximity_chars.h
@@ -40,8 +40,9 @@
     static const int32_t EN_US_ADDITIONAL_U[];
 
     static bool isEnLocale(const std::string *locale_str) {
-        return locale_str && locale_str->size() >= LOCALE_EN_US.size()
-                && LOCALE_EN_US.compare(0, LOCALE_EN_US.size(), *locale_str);
+        const size_t LOCALE_EN_US_SIZE = LOCALE_EN_US.size();
+        return locale_str && locale_str->size() >= LOCALE_EN_US_SIZE
+                && locale_str->compare(0, LOCALE_EN_US_SIZE, LOCALE_EN_US) == 0;
     }
 
  public:
@@ -84,10 +85,6 @@
             return 0;
         }
     }
-
-    static bool hasAdditionalChars(const std::string *locale_str, const int32_t c) {
-        return getAdditionalCharsSize(locale_str, c) > 0;
-    }
 };
 } // namespace latinime
 #endif // LATINIME_ADDITIONAL_PROXIMITY_CHARS_H