Switch "dsvm-functional:" into same pattern as constraints

In Ibdfc03f27450a5392acc276f98bfb464f9a0f663, the oslo team is
adding some periodic jobs to run oslo.* from master against
neutron's py27 and py34, this is done by extending the
existing tox targets. The presence of "dsvm-functional:" in
commands breaks the jobs.

The right way to fix this is to follow the same pattern
as the constraints by defining it once in
[testenv:dsvm-functional] and reusing it. However this will
not work as there is a bug in tox with posargs that Sachi just fixed:
https://bitbucket.org/hpk42/tox/pull-requests/189/fix-section-substitution-with-posargs/diff

So until we have a version of tox in our CI images with that
fix, we need to live with duplicate definitions.

Change-Id: I8880bf9caa269b9183dba8f269760af76461bca1

tox.ini

@@ -14,7 +14,6 @@ deps = -r{toxinidir}/requirements.txt
        -r{toxinidir}/test-requirements.txt
 whitelist_externals = sh
 commands =
-  dsvm-functional: {toxinidir}/tools/deploy_rootwrap.sh {toxinidir} {envdir}/etc {envdir}/bin
   {toxinidir}/tools/ostestr_compat_shim.sh {posargs}
 # there is also secret magic in ostestr which lets you run in a fail only
 # mode. To do this define the TRACE_FAILONLY environmental variable.
@@ -81,6 +80,9 @@ setenv = {[testenv:functional]setenv}
 sitepackages=True
 deps =
   {[testenv:functional]deps}
+commands =
+  {toxinidir}/tools/deploy_rootwrap.sh {toxinidir} {envdir}/etc {envdir}/bin
+  {toxinidir}/tools/ostestr_compat_shim.sh {posargs}
 
 [testenv:dsvm-functional-constraints]
 basepython = {[testenv:dsvm-functional]basepython}
@@ -89,6 +91,9 @@ setenv = {[testenv:dsvm-functional]setenv}
 sitepackages={[testenv:dsvm-functional]sitepackages}
 deps =
   {[testenv:functional-constraints]deps}
+commands =
+  {toxinidir}/tools/deploy_rootwrap.sh {toxinidir} {envdir}/etc {envdir}/bin
+  {toxinidir}/tools/ostestr_compat_shim.sh {posargs}
 
 [testenv:dsvm-functional-py34]
 basepython = python3.4
@@ -96,6 +101,9 @@ setenv = {[testenv:dsvm-functional]setenv}
 sitepackages={[testenv:dsvm-functional]sitepackages}
 deps =
   {[testenv:dsvm-functional]deps}
+commands =
+  {toxinidir}/tools/deploy_rootwrap.sh {toxinidir} {envdir}/etc {envdir}/bin
+  {toxinidir}/tools/ostestr_compat_shim.sh {posargs}
 
 [testenv:dsvm-fullstack]
 setenv = {[testenv]setenv}