Windows Deployment Guide needs minor update for MinGW

I think QTBUG-7676 was closed incorrectly (and don't see any way to require reopening it without creating another issue).

Perhaps the problem description was unclear.

The Windows Deployment Guide explains how to use Dependency Walker to find dependencies. It gives an example of finding dependencies for the Plug & Paint sample, and says that (with MinGW) the only dependency is on MINGWM10.DLL.

But a recent change in MinGW means this example is now wrong. If users check dependencies for the Plug & Paint sample (or any Qt program built using default settings) they'll see an additional dependency on LIBGCC_S_DW2-1.DLL.

I suggest listing LIBGCC_S_DW2-1.DLL too. One reason is, as above, that the documentation is simply incorrect when it says MINGWM10.DLL will be the only dependency if you examine the Plug & Paint sample.

But another reason is that it's helpful to new Qt users to know that LIBGCC_S_DW2-1.DLL is supposed to show up as a dependency, that it's not an indication that their program was built incorrectly or a "problem" they need to address, but a required part of MinGW. (Thus, it would be better to list LIBGCC_S_DW2-1.DLL than to remove all references to specific DLL names and tell people to just use Dependency Walker to find all names.)