always $-escape make commands

nmake needs %-escaping in addition to $-escaping, not instead.
this has little practical impact, so it went unnoticed.

Change-Id: I144b6142eec0151d83a22e0ac5ead7b0415cdafa
Reviewed-by: Joerg Bornemann <joerg.bornemann@digia.com>

mkspecs/features/qt_functions.prf

@@ -226,7 +226,7 @@ defineTest(qtAddToolEnv) {
             }
             !contains(TEMPLATE, vc.*) {
                 contains(MAKEFILE_GENERATOR, MS.*): val ~= s,%,%%,g
-                else: val ~= s,\\\$,\$\$,g
+                val ~= s,\\\$,\$\$,g
             }
             $$1 = "$$val $$eval($$1)"
         }