Fixing some warnings on Linux

There were only a few warnings left, so I fixed them and enabled the unused variable warning by removing the "-Wno-unused" flag. Only the -Wno-unused-parameter remains for now (could be removed later).
Review URL: https://codereview.chromium.org/12480002

git-svn-id: http://skia.googlecode.com/svn/trunk@8030 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/samplecode/SampleTextAlpha.cpp b/samplecode/SampleTextAlpha.cpp
index 8a248c3..59ce186 100644
--- a/samplecode/SampleTextAlpha.cpp
+++ b/samplecode/SampleTextAlpha.cpp
@@ -94,7 +94,7 @@
         }
     }
 
-    virtual SkView::Click* onFindClickHandler(SkScalar x, SkScalar y) {
+    virtual SkView::Click* onFindClickHandler(SkScalar x, SkScalar y, unsigned) SK_OVERRIDE {
         return new Click(this);
     }