fixup: skip only 18 WCHAR if keyName begins with \\registry\\machine

Note that keyName was declared char * in the original code.
But now it is WCHAR*, so keyName+18 already does the right thing (skip 18 char) while modified code would now skip 36!
Note that original code was using memcpy for this case of overlapping memory which is BAD and eventually UB.
[skip travis]

platforms/win32/vm/sqWin32Main.c

@@ -732,7 +732,7 @@ void gatherSystemInfo(void) {
        I have no idea why but for now I'll just truncate that part if
        we recognize it... */
     if (_wcsnicmp(keyName, L"\\registry\\machine\\", 18) == 0) {
-      memmove(keyName, keyName+18*sizeof(WCHAR), (wcslen(keyName)-17)*sizeof(WCHAR));
+      memmove(keyName, keyName+18, (wcslen(keyName)+1-18)*sizeof(WCHAR)); /* +1 for terminating NULL */
     }
 
     ok = RegOpenKeyW(HKEY_LOCAL_MACHINE, keyName, &hk);