ARROW-65: Be less restrictive on PYTHON_LIBRARY search paths

Current CMake FindPythonLibs also uses this option instead of NO_DEFAULT_PATH.

Author: Uwe L. Korn <uwelk@xhochy.com>

Closes #43 from xhochy/arrow-65 and squashes the following commits:

10eb9e0 [Uwe L. Korn] ARROW-65: Be less restrictive on PYTHON_LIBRARY search paths

python/cmake_modules/FindPythonLibsNew.cmake

@@ -166,7 +166,7 @@ else()
     find_library(PYTHON_LIBRARY
         NAMES "python${PYTHON_LIBRARY_SUFFIX}"
         PATHS ${_PYTHON_LIBS_SEARCH}
-        NO_DEFAULT_PATH)
+        NO_SYSTEM_ENVIRONMENT_PATH)
     message(STATUS "Found Python lib ${PYTHON_LIBRARY}")
 endif()