Fix Appveyor builds.

appveyor.yml

@@ -1,5 +1,5 @@
 # Copyright (c) 2014, Ruslan Baratov
-# Copyright (c) 2014, Alexander Lamaison
+# Copyright (c) 2014, 2016 Alexander Lamaison
 # All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
@@ -41,9 +41,9 @@ platform:
   - x86
   - x64
 
-# configuration:
-#   - Debug
-#   - Release
+configuration:
+# - Debug
+  - Release
 
 build_script:
   - ps: if($env:PLATFORM -eq "x64") { $env:CMAKE_GEN_SUFFIX=" Win64" }
@@ -55,5 +55,5 @@ test_script:
   - ctest -VV -C "%CONFIGURATION%" --output-on-failure
 
 on_failure:
-  - ps: cat _builds/CMakeFiles/CMakeOutput.log
-  - ps: cat _builds/CMakeFiles/CMakeError.log
+  - ps: if (Test-Path _builds/CMakeFiles/CMakeOutput.log) { cat _builds/CMakeFiles/CMakeOutput.log }
+  - ps: if (Test-Path _builds/CMakeFiles/CMakeError.log) { cat _builds/CMakeFiles/CMakeError.log }