DfsBlockCache: Suppress warnings about unchecked conversion of Ref<T>

There are already suppressions for the same warnings in other parts
of this class.

Change-Id: Ic3b45525c6c8200cba975d14c7650cedb4409a4d
Signed-off-by: David Pursehouse <david.pursehouse@gmail.com>

org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/dfs/DfsBlockCache.java

@@ -175,6 +175,7 @@ public final class DfsBlockCache {
 	/** Number of bytes currently loaded in the cache. */
 	private volatile long liveBytes;
 
+	@SuppressWarnings("unchecked")
 	private DfsBlockCache(final DfsBlockCacheConfig cfg) {
 		tableSize = tableSize(cfg);
 		if (tableSize < 1)
@@ -416,6 +417,7 @@ public final class DfsBlockCache {
 		clockLock.unlock();
 	}
 
+	@SuppressWarnings("unchecked")
 	private void addToClock(Ref ref, int credit) {
 		clockLock.lock();
 		try {