[tox] Cannot use requirements/dev.txt in the same pip line

tox.ini

@@ -12,8 +12,8 @@ basepython = python3.2
 deps = -r{toxinidir}/requirements/default.txt
        -r{toxinidir}/requirements/test3.txt
        -r{toxinidir}/requirements/test-ci.txt
-       -r{toxinidir}/requirements/dev.txt
 commands = {toxinidir}/extra/release/removepyc.sh {toxinidir}
+           pip install -r{toxinidir}/requirements/dev.txt
            pip install anyjson
            nosetests -vd celery.tests                          \
                --with-xunit                                    \
@@ -25,8 +25,8 @@ basepython = python3.3
 deps = -r{toxinidir}/requirements/default.txt
        -r{toxinidir}/requirements/test3.txt
        -r{toxinidir}/requirements/test-ci.txt
-       -r{toxinidir}/requirements/dev.txt
 commands = {toxinidir}/extra/release/removepyc.sh {toxinidir}
+           pip install -r{toxinidir}/requirements/dev.txt
            pip install anyjson
            nosetests -vd celery.tests                          \
                --with-xunit                                    \
@@ -37,8 +37,8 @@ basepython = python2.7
 deps = -r{toxinidir}/requirements/default.txt
        -r{toxinidir}/requirements/test.txt
        -r{toxinidir}/requirements/test-ci.txt
-       -r{toxinidir}/requirements/dev.txt
 commands = {toxinidir}/extra/release/removepyc.sh {toxinidir}
+           pip install -r{toxinidir}/requirements/dev.txt
            pip install anyjson
            nosetests --with-xunit                               \
                      --xunit-file={toxinidir}/nosetests.xml     \
@@ -51,8 +51,8 @@ basepython = python2.6
 deps = -r{toxinidir}/requirements/default.txt
        -r{toxinidir}/requirements/test.txt
        -r{toxinidir}/requirements/test-ci.txt
-       -r{toxinidir}/requirements/dev.txt
 commands = {toxinidir}/extra/release/removepyc.sh {toxinidir}
+           pip install -r{toxinidir}/requirements/dev.txt
            pip install anyjson
            nosetests --with-xunit                               \
                      --xunit-file={toxinidir}/nosetests.xml     \
@@ -65,8 +65,8 @@ basepython = pypy
 deps = -r{toxinidir}/requirements/default.txt
        -r{toxinidir}/requirements/test.txt
        -r{toxinidir}/requirements/test-ci.txt
-       -r{toxinidir}/requirements/dev.txt
 commands = {toxinidir}/extra/release/removepyc.sh {toxinidir}
+           pip install -r{toxinidir}/requirements/dev.txt
            pip install anyjson
            nosetests --with-xunit                               \
                      --xunit-file={toxinidir}/nosetests.xml     \