Remove old excludes

These are detected as errors since the clean up was done[1] in
the requirements repository.

[1] 314734e938f107cbd5ebcc7af4d9167c11347406

Change-Id: Iaa93d3f5014d140409f8663bfaf91606297e6516
diff --git a/requirements.txt b/requirements.txt
index ed5a98c..d9e5e0c 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -15,4 +15,4 @@
 testscenarios>=0.4 # Apache-2.0/BSD
 tempest>=17.1.0 # Apache-2.0
 gabbi>=1.42.1 # Apache-2.0
-kombu!=4.0.2,>=4.0.0 # BSD
+kombu>=4.0.0 # BSD