win32: don't set error mode

Commit a8c63f2 (win32: improve filesystem detection and display)
added a call to SetErrorMode(SEM_FAILCRITICALERRORS).  This was
on the strength of the documentation for GetVolumeInformation()
which suggests that otherwise a message box will appear to prompt
the user to put media in an empty floppy or CD drive.  This would
disrupt the expected behaviour of applets like 'df'.

In practice it seems the call to SetErrorMode() is unnecessary.
It also results in other errors going unreported.

Remove the call to SetErrorMode().

Saves 8-20 bytes.

(GitHub issue #423)

libbb/appletlib.c

@@ -1349,10 +1349,6 @@ int main(int argc UNUSED_PARAM, char **argv)
 			break;
 		}
 	}
-
-	/* Ignore critical errors, such as calling GetVolumeInformation() on
-	 * a floppy or CDROM drive with no media. */
-	SetErrorMode(SEM_FAILCRITICALERRORS);
 #endif
 
 #if defined(__MINGW64_VERSION_MAJOR)