I'm a little late to the game here, but the simple answer is to move the H4 AFTER the button div. This is a common issue when floating, always have your floats defined BEFORE the rest of the contents or you'll have that extra line-break problem.
<div class="panel-heading">
<div class="btn-group pull-right">
<a href="#" class="btn btn-default btn-sm">## Lock</a>
<a href="#" class="btn btn-default btn-sm">## Delete</a>
<a href="#" class="btn btn-default btn-sm">## Move</a>
</div>
<h4>Panel header</h4>
</div>
The issue here is that when your floats are defined after other items, the float's top will start at the last line-position of the element immediately before it. So, if the previous item wraps to line 3, your float will start at line 3 too.
Moving the float to the TOP of the list eliminates the issue because there are no previous elements to push it down and anything after the float will be rendered at the top line (assuming there is room on the line for all items)
Example of correct and incorrect ordering and the effects: http://www.bootply.com/HkDlNIKv9g