perf python: Properly link with libtraceevent

Namhyung Kim reported that the build fails with:

  GEN python/perf.so
  gcc: error: python_ext_build/tmp//../../libtraceevent.a: No such file or directory
  error: command 'gcc' failed with exit status 1
  cp: cannot stat `python_ext_build/lib/perf.so': No such file or directory
  make: *** [python/perf.so] Error 1

We need to propagate the TE_PATH variable to the setup.py file.

Reported-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Link: http://lkml.kernel.org/n/tip-8umiPbm4sxpknKivbjgykhut@git.kernel.org
[ Fixed superfluous variable build error. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
diff --git a/tools/perf/util/setup.py b/tools/perf/util/setup.py
index 09c3cea..73d5102 100644
--- a/tools/perf/util/setup.py
+++ b/tools/perf/util/setup.py
@@ -23,6 +23,7 @@
 
 build_lib = getenv('PYTHON_EXTBUILD_LIB')
 build_tmp = getenv('PYTHON_EXTBUILD_TMP')
+libtraceevent = getenv('LIBTRACEEVENT')
 
 ext_sources = [f.strip() for f in file('util/python-ext-sources')
 				if len(f.strip()) > 0 and f[0] != '#']
@@ -31,7 +32,7 @@
 		  sources = ext_sources,
 		  include_dirs = ['util/include'],
 		  extra_compile_args = cflags,
-		  extra_objects = [build_tmp + '/../../libtraceevent.a'],
+		  extra_objects = [libtraceevent],
                  )
 
 setup(name='perf',