Using Where.exe causes Build scripts using Gallio to fail.

We use TFS and Gallio in our build scripts.  Recently, I added some tests using Approval Tests to my code base. The build script started breaking with the following message repeated 7 times.

[ERROR] INFO: Could not find files for the given pattern(s)

I used SysInternals' ProcMon to track the issue down and found that the ApprovalTests were looking for 7 different diff tools that I didn't have.  That correlated with the 7 repeats.  I also found in my investigations that the only program that displayed that exact error message was the 'where.exe' utility.

I tracked that down to the included file and rewrote the process to use a much simpler path search that doesn't throw any extraneous errors.

This patch fixed my build breakage as well.