Remove qoutes from env vars

appveyor.yml

@@ -4,13 +4,13 @@ configuration: Release
 environment:
   matrix:
   - ARCH: 32
-    GENERATOR: '"Visual Studio 11"'
+    GENERATOR: 'Visual Studio 11'
-    PYTHON: '"C:\Python35\python.exe"'
+    PYTHON: 'C:\Python35\python.exe'
-    PIP: '"C:\Python35\Scripts\pip.exe"'
+    PIP: 'C:\Python35\Scripts\pip.exe'
   - ARCH: 64
-    GENERATOR: '"Visual Studio 11 Win64"'
+    GENERATOR: 'Visual Studio 11 Win64'
-    PYTHON: '"C:\Python35-x64\python.exe"'
+    PYTHON: 'C:\Python35-x64\python.exe'
-    PIP: '"C:\Python35-x64\Scripts\pip.exe"'
+    PIP: 'C:\Python35-x64\Scripts\pip.exe'
 build_script:
 - cmd: |
     set LIBGIT2=%APPVEYOR_BUILD_FOLDER%\build\libgit2
@@ -18,13 +18,13 @@ build_script:
     mkdir build
     
     cd build
-    cmake -DSTDCALL=OFF -DBUILD_CLAR=OFF -DCMAKE_INSTALL_PREFIX=%LIBGIT2% ../libgit2 -G %GENERATOR%
+    cmake -DSTDCALL=OFF -DBUILD_CLAR=OFF -DCMAKE_INSTALL_PREFIX="%LIBGIT2%" ../libgit2 -G "%GENERATOR%"
     cmake --build . --config Release --target install
     cd ..
     
-    %PIP% install wheel
+    "%PIP%" install wheel
-    %PYTHON% setup.py bdist_wheel 
+    "%PYTHON%" setup.py bdist_wheel 
-    %PIP% install .
+    "%PIP%" install .
     
 test_script:
 - ps: >-