[SCons] Remove check for <tr1/tuple>

Updated gtest version makes this special case unnecessary.

SConstruct

@@ -811,7 +811,6 @@ env['HAS_TIMES_H'] = conf.CheckCHeader('sys/times.h', '""')
 env['HAS_UNISTD_H'] = conf.CheckCHeader('unistd.h', '""')
 env['HAS_MATH_H_ERF'] = conf.CheckDeclaration('erf', '#include <math.h>', 'C++')
 env['HAS_BOOST_MATH'] = conf.CheckCXXHeader('boost/math/special_functions/erf.hpp', '<>')
-env['HAS_TR1_TUPLE'] = conf.CheckCXXHeader('tr1/tuple', '<>')
 boost_version_source = get_expression_value(['<boost/version.hpp>'], 'BOOST_LIB_VERSION')
 retcode, boost_lib_version = conf.TryRun(boost_version_source, '.cpp')
 env['BOOST_LIB_VERSION'] = boost_lib_version.strip()

ext/SConscript

@@ -159,8 +159,6 @@ localenv = env.Clone()
 localenv.Prepend(CPPPATH=[Dir('#ext/gtest'),
                           Dir('#ext/gtest/include')],
                  CPPDEFINES={'GTEST_HAS_PTHREAD': 0})
-if not localenv['HAS_TR1_TUPLE']:
-    localenv.Append(CPPDEFINES='GTEST_USE_OWN_TR1_TUPLE')
 
 gtest = build(localenv.Library(pjoin('../lib', 'gtest'),
                               source=['gtest/src/gtest-all.cc']))

test/SConscript

@@ -9,9 +9,6 @@ localenv.Prepend(CPPPATH=['#ext/gtest/include', '#include'],
 localenv.Append(LIBS=['gtest'] + localenv['cantera_libs'],
                 CCFLAGS=env['warning_flags'])
 
-if not localenv['HAS_TR1_TUPLE']:
-    localenv.Append(CPPDEFINES='GTEST_USE_OWN_TR1_TUPLE')
-
 localenv['ENV']['CANTERA_DATA'] = Dir('#build/data').abspath
 
 PASSED_FILES = {}