Replace ProGuard 5.3.3 with Google internal version.

Bug:
Change-Id: Ic49612a51691df3ac746378de8d978c71da08607
diff --git a/third_party/proguard/proguard_internal_159423826.tar.gz.sha1 b/third_party/proguard/proguard_internal_159423826.tar.gz.sha1
new file mode 100644
index 0000000..8fdbf19
--- /dev/null
+++ b/third_party/proguard/proguard_internal_159423826.tar.gz.sha1
@@ -0,0 +1 @@
+933e970c611a306ef5d755234820188bc50c4c60
\ No newline at end of file