Windows-build: improve handling failures in gnutls build-steps

Change-Id: I765959e1ac73ca8d0315d1ee85b18cbb0b4cf92b

contrib/src/gnutls/package.json

@@ -15,9 +15,9 @@
     "custom_scripts": {
         "pre_build": [
             "git init",
-            "git remote add origin https://github.com/ShiftMediaProject/gnutls.git || true",
+            "git remote add origin https://github.com/ShiftMediaProject/gnutls.git || exit /b 0",
             "git fetch origin --depth=1 --tags && git reset --hard 3.8.3",
-            "git apply ../../src/gnutls/0001-fix-mkdir-permissions-on-Windows.patch",
+            "git apply --whitespace=fix ../../src/gnutls/0001-fix-mkdir-permissions-on-Windows.patch",
             "git submodule update --init --recursive --depth=1 gnulib devel/libtasn1"
         ]
     }