Don't append _build to the directory name of tests expected to fail.

The name passed to the project() command must be the same as the argument
to ctest --build-project.

Initially I had appended _build to disambiguate the generated project
from the project under test, but that is not needed anyway as the
project under test is self-contained, so it's ok.

Task-number: QTBUG-27087
Change-Id: I648d57271529d4e8d308ff60b81419ade29b2e44
Reviewed-by: Rohan McGovern <rohan.mcgovern@nokia.com>

src/corelib/Qt5CTestMacros.cmake

@@ -34,7 +34,7 @@ macro(expect_fail _dir)
   file(WRITE "${CMAKE_CURRENT_BINARY_DIR}/failbuild/${_dir}/CMakeLists.txt"
     "
       cmake_minimum_required(VERSION 2.8)
-      project(${_dir}_build)
+      project(${_dir})
 
       try_compile(Result \${CMAKE_CURRENT_BINARY_DIR}/${_dir}
           \${CMAKE_CURRENT_SOURCE_DIR}/${_dir}