Add release checksums for libogg-1.3.3 source packages.

These should match http://downloads.xiph.org/releases/ogg/SHA256SUMS
diff --git a/releases.sha2 b/releases.sha2
index 5cc3aeb..a37cd57 100644
--- a/releases.sha2
+++ b/releases.sha2
@@ -32,3 +32,6 @@
 e19ee34711d7af328cb26287f4137e70630e7261b17cbe3cd41011d73a654692  libogg-1.3.2.tar.gz
 3f687ccdd5ac8b52d76328fbbfebc70c459a40ea891dbf3dccb74a210826e79b  libogg-1.3.2.tar.xz
 957b4168a03932e02853db340cfddd0fa89b6ca80073a54f7c827372c3606350  libogg-1.3.2.zip
+c2e8a485110b97550f453226ec644ebac6cb29d1caef2902c007edab4308d985  libogg-1.3.3.tar.gz
+4f3fc6178a533d392064f14776b23c397ed4b9f48f5de297aba73b643f955c08  libogg-1.3.3.tar.xz
+ddbb0884406ea2b30d831dc7304fd4a958a05d62f24429d8fa83e1c9d620e7f8  libogg-1.3.3.zip