Reset mUnmodifiedDataUse after bufferSubData

Without this, enough draws from a buffer modified only with bufferSubData will cause it to switch become static.

BUG=
TEST=

Review URL: http://codereview.appspot.com/5123042

git-svn-id: http://angleproject.googlecode.com/svn/trunk@769 736b8ea6-26fd-11df-bfd4-992fa37f6226
diff --git a/src/common/version.h b/src/common/version.h
index 9c7e56b..7777a4e 100644
--- a/src/common/version.h
+++ b/src/common/version.h
@@ -1,7 +1,7 @@
 #define MAJOR_VERSION 0
 #define MINOR_VERSION 0
 #define BUILD_VERSION 0
-#define BUILD_REVISION 768
+#define BUILD_REVISION 769
 
 #define STRINGIFY(x) #x
 #define MACRO_STRINGIFY(x) STRINGIFY(x)
diff --git a/src/libGLESv2/Buffer.cpp b/src/libGLESv2/Buffer.cpp
index 2cd148e..dd12e3c 100644
--- a/src/libGLESv2/Buffer.cpp
+++ b/src/libGLESv2/Buffer.cpp
@@ -74,6 +74,8 @@
     {
         invalidateStaticData();
     }
+
+    mUnmodifiedDataUse = 0;
 }
 
 StaticVertexBuffer *Buffer::getStaticVertexBuffer()