Update autotest tests to use make -j where possible.

This cuts the time required to build the autotests from 7m30s to
about 4m10s on my z600.

TEST=Ran ./autotest --build=all
BUG=chromium-os:5309

Review URL: http://codereview.chromium.org/3116009
diff --git a/client/deps/ibusclient/ibusclient.py b/client/deps/ibusclient/ibusclient.py
index 21f646c..d7f3561 100755
--- a/client/deps/ibusclient/ibusclient.py
+++ b/client/deps/ibusclient/ibusclient.py
@@ -12,7 +12,7 @@
 def setup(topdir):
     srcdir = os.path.join(topdir, 'src')
     os.chdir(srcdir)
-    utils.system('make')
+    utils.make()
     os.chdir(topdir)
 
 pwd = os.getcwd()