Update the Tuning Guide figure about using the statement cache

The second figure in file ctundepth32379.dita needs to be updated.

These comments came from Stan Bradbury as part of his review for Derby-1842

Fig 2 : The graphic is not correct - I suggest a horizontal line separating Connection One and Connection Two (line should run under the TOP select, it's three exection-arrows and the TOP Statement Object) - label: 'Connection One' should be ABOVE the Select statement and FIRST execution-arrow for the Connection (not below an execution-arrow).
Label 'Connection Two' should be above the SECOND select (below the added line) and it's FIRST execution-arrow (the second solid arrow). This arrow needs to be the only arrow pointing to the SECOND Statement Object.
Replace the dotted line at the bottom with a STRAIGTH, SOLID line that runs STRAIGHT between the BOTTOM select statement and the BOTTOM (third) Statement Object. There is no 'elbow' arrow for the second connection.
It is not clear that the only the TOP select AND the TOP Statement Object are part of Connection One. All three Connection One execution-arrows need to point to the SAME (TOP) Statement Object. The next TWO selects, exectuion-arrows and Statement Objects need to be in do not line up properly . --The arrows between the Statment Objects and the Statement Cache pages are good.