Make platform-detection code tolerate linux-3.0, patch by zooko.

Otherwise address-autodetection can't find ifconfig. refs #1536

src/allmydata/test/test_encodingutil.py

@@ -211,6 +211,7 @@ class EncodingUtil(ReallyEqualMixin):
     def test_unicode_platform(self):
         matrix = {
           'linux2': False,
+          'linux3': False,
           'openbsd4': False,
           'win32':  True,
           'darwin': True,

src/allmydata/test/test_system.py

@@ -1398,7 +1398,7 @@ class SystemTest(SystemTestMixin, RunBinTahoeMixin, unittest.TestCase):
             self.failUnlessEqual(data, expected_data)
         d.addCallback(_check)
         d.addCallback(lambda res: rref.callRemote("speed_test", 1, 200, False))
-        if sys.platform == "linux2":
+        if sys.platform in ("linux2", "linux3"):
             d.addCallback(lambda res: rref.callRemote("get_memory_usage"))
         d.addCallback(lambda res: rref.callRemote("measure_peer_response_time"))
         return d

src/allmydata/util/iputil.py

@@ -139,6 +139,7 @@ _platform_map = {
     "linux-i386": "linux", # redhat
     "linux-ppc": "linux",  # redhat
     "linux2": "linux",     # debian
+    "linux3": "linux",     # debian
     "win32": "win32",
     "irix6-n32": "irix",
     "irix6-n64": "irix",