Fix quoting in a setx command used when testing Fruit on Windows in AppVeyor.
diff --git a/appveyor.yml b/appveyor.yml
index fbad46a..8df60fe 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -18,6 +18,6 @@
     CMAKE_GENERATOR: '"Visual Studio 15 2017 Win64"'
     VCVARSALL_SCRIPT: '"C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\VC\Auxiliary\Build\vcvarsall.bat"'
 install:
-- cmd: setx PATH %PATH:C:\Program Files\Git\usr\bin;=%
+- cmd: setx PATH "%PATH:C:\Program Files\Git\usr\bin;=%"
 build_script:
 - cmd: C:\Fruit\extras\scripts\postsubmit.bat