delete -> free

Strings duplicated with strdup() should be free()d, not deleted.

Change-Id: I42bb3df9625bb8d35f80b02d15364b94c36496f8
diff --git a/media/libmedia/SoundPool.cpp b/media/libmedia/SoundPool.cpp
index 204e0ce..ee70ef7 100644
--- a/media/libmedia/SoundPool.cpp
+++ b/media/libmedia/SoundPool.cpp
@@ -489,7 +489,7 @@
         ::close(mFd);
     }
     mData.clear();
-    delete mUrl;
+    free(mUrl);
 }
 
 status_t Sample::doLoad()