Remove unneeded catch block and null checks

The catched exception was just rethrown and the
null check of the locked dir cache was unneeded if
the assignment was done outside the try block.

Change-Id: If2ee1f3eff3849f8da51eab825057fc56e166a94

org.eclipse.jgit/src/org/eclipse/jgit/api/ResetCommand.java

@@ -312,35 +312,27 @@ public class ResetCommand extends GitCommand<Ref> {
 	}
 
 	private void resetIndex(RevCommit commit) throws IOException {
-		DirCache dc = null;
+		DirCache dc = repo.lockDirCache();
 		try {
-			dc = repo.lockDirCache();
 			dc.clear();
 			DirCacheBuilder dcb = dc.builder();
 			dcb.addTree(new byte[0], 0, repo.newObjectReader(),
 					commit.getTree());
 			dcb.commit();
-		} catch (IOException e) {
-			throw e;
 		} finally {
-			if (dc != null)
-				dc.unlock();
+			dc.unlock();
 		}
 	}
 
 	private void checkoutIndex(RevCommit commit) throws IOException {
-		DirCache dc = null;
+		DirCache dc = repo.lockDirCache();
 		try {
-			dc = repo.lockDirCache();
 			DirCacheCheckout checkout = new DirCacheCheckout(repo, dc,
 					commit.getTree());
 			checkout.setFailOnConflict(false);
 			checkout.checkout();
-		} catch (IOException e) {
-			throw e;
 		} finally {
-			if (dc != null)
-				dc.unlock();
+			dc.unlock();
 		}
 	}