Tox is broken

tox.ini

@@ -13,7 +13,7 @@ deps = -r{toxinidir}/requirements/default.txt
        -r{toxinidir}/requirements/test3.txt
        -r{toxinidir}/requirements/test-ci.txt
 commands = {toxinidir}/extra/release/removepyc.sh {toxinidir}
-           pip install http://github.com/celery/kombu/zipball/master
+           pip install -U http://github.com/celery/kombu/zipball/master
            nosetests -vd celery.tests                          \
                --with-coverage3                                \
                  --cover3-branch                               \
@@ -32,8 +32,8 @@ basepython = python3.3
 deps = -r{toxinidir}/requirements/default.txt
        -r{toxinidir}/requirements/test3.txt
        -r{toxinidir}/requirements/test-ci.txt
-       http://github.com/celery/kombu/zipball/master
 commands = {toxinidir}/extra/release/removepyc.sh {toxinidir}
+           pip install -U http://github.com/celery/kombu/zipball/master
            nosetests -vd celery.tests                          \
                --with-coverage3                                \
                  --cover3-branch                               \
@@ -51,8 +51,8 @@ basepython = python2.7
 deps = -r{toxinidir}/requirements/default.txt
        -r{toxinidir}/requirements/test.txt
        -r{toxinidir}/requirements/test-ci.txt
-       http://github.com/celery/kombu/zipball/master
 commands = {toxinidir}/extra/release/removepyc.sh {toxinidir}
+           pip install -U http://github.com/celery/kombu/zipball/master
            nosetests --with-xunit                               \
                      --xunit-file={toxinidir}/nosetests.xml     \
                      --with-coverage3 --cover3-xml              \
@@ -64,8 +64,8 @@ basepython = python2.6
 deps = -r{toxinidir}/requirements/default.txt
        -r{toxinidir}/requirements/test.txt
        -r{toxinidir}/requirements/test-ci.txt
-       http://github.com/celery/kombu/zipball/master
 commands = {toxinidir}/extra/release/removepyc.sh {toxinidir}
+           pip install -U http://github.com/celery/kombu/zipball/master
            nosetests --with-xunit                               \
                      --xunit-file={toxinidir}/nosetests.xml     \
                      --with-coverage3 --cover3-xml              \
@@ -77,8 +77,8 @@ basepython = pypy
 deps = -r{toxinidir}/requirements/default.txt
        -r{toxinidir}/requirements/test.txt
        -r{toxinidir}/requirements/test-ci.txt
-       http://github.com/celery/kombu/zipball/master
 commands = {toxinidir}/extra/release/removepyc.sh {toxinidir}
+           pip install -U http://github.com/celery/kombu/zipball/master
            nosetests --with-xunit                               \
                      --xunit-file={toxinidir}/nosetests.xml     \
                      --with-coverage3 --cover3-xml              \