Preinstall requirements for docs build and fix lower constraints

Sphinx installs the package with its dependencies, but it does not use
the constraints. This can lead to errors if a dependency introduces any
backward incompatible changes. To avoid this the dependencies needs to
be installed prior to sphinx run by tox with the correct constraints.

Conflicts:
    tox.ini

NOTE(elod.illes):
* conflict is due to branch specific upper constraints setting patch.
* sahara-openstack-ansible-functional job is passing in victoria so
  that part is not needed in stable/victoria
* this patch also corrects the contradicting lower constraints to make
  the lower-constraints job pass (with the new pip dependency resolver,
  introduced in pip 20.3, the job started to show the contradictions
  and thus started to fail):
  - oslo.service 1.24.0 version contradicts with eventlet 0.26.0 lower
    constraint
  - alembic 0.9.6 is required for oslo.db 6.0.0
  - cryptography 2.5 is required for paramiko 2.7.1
  - amqp 2.6.0 is required for kombu 5.0.1
  - warlock 1.3.1 is required for jsonschema 3.2.0
  - six 1.11.0 is in requirements.txt, update to same in l-c.txt

Change-Id: I4ba83f1007dd11801b8e32c6d7566769e005480b
(cherry picked from commit e0136189fc)
(cherry picked from commit 0900fc028c)

lower-constraints.txt

@@ -1,6 +1,6 @@
 alabaster==0.7.10
-alembic==0.8.10
-amqp==2.2.2
+alembic==0.9.6
+amqp==2.6.0
 appdirs==1.4.3
 asn1crypto==0.24.0
 astroid==1.3.8
@@ -18,7 +18,7 @@ cliff==2.11.0
 cmd2==0.8.1
 contextlib2==0.5.5
 coverage==4.0
-cryptography==2.1.4
+cryptography==2.5
 debtcollector==1.19.0
 decorator==4.2.1
 deprecation==2.0
@@ -78,7 +78,7 @@ oslo.middleware==3.31.0
 oslo.policy==1.30.0
 oslo.rootwrap==5.8.0
 oslo.serialization==2.18.0
-oslo.service==1.24.0
+oslo.service==1.31.0
 oslo.upgradecheck==0.1.0
 oslo.utils==3.33.0
 oslotest==3.2.0
@@ -128,7 +128,7 @@ restructuredtext-lint==1.1.3
 rfc3986==1.1.0
 Routes==2.4.1
 simplejson==3.13.2
-six==1.10.0
+six==1.11.0
 smmap2==2.0.3
 snowballstemmer==1.2.1
 Sphinx==1.6.2
@@ -151,7 +151,7 @@ unittest2==1.1.0
 urllib3==1.22
 vine==1.1.4
 voluptuous==0.11.1
-warlock==1.3.0
+warlock==1.3.1
 WebOb==1.7.1
 Werkzeug==0.14.1
 wrapt==1.10.11

requirements.txt

@@ -4,7 +4,7 @@
 
 pbr!=2.1.0,>=2.0.0 # Apache-2.0
 
-alembic>=0.8.10 # MIT
+alembic>=0.9.6 # MIT
 botocore>=1.5.1 # Apache-2.0
 castellan>=0.16.0 # Apache-2.0
 eventlet>=0.26.0 # MIT
@@ -26,7 +26,7 @@ oslo.middleware>=3.31.0 # Apache-2.0
 oslo.policy>=1.30.0 # Apache-2.0
 oslo.rootwrap>=5.8.0 # Apache-2.0
 oslo.serialization!=2.19.1,>=2.18.0 # Apache-2.0
-oslo.service!=1.28.1,>=1.24.0 # Apache-2.0
+oslo.service>=1.31.0 # Apache-2.0
 oslo.upgradecheck>=0.1.0 # Apache-2.0
 oslo.utils>=3.33.0 # Apache-2.0
 paramiko>=2.7.1 # LGPLv2.1+
@@ -39,7 +39,7 @@ python-swiftclient>=3.2.0 # Apache-2.0
 python-neutronclient>=6.7.0 # Apache-2.0
 python-heatclient>=1.10.0 # Apache-2.0
 python-glanceclient>=2.8.0 # Apache-2.0
-six>=1.10.0 # MIT
+six>=1.11.0 # MIT
 stevedore>=1.20.0 # Apache-2.0
 SQLAlchemy!=1.1.5,!=1.1.6,!=1.1.7,!=1.1.8,>=1.0.10 # MIT
 tooz>=1.58.0 # Apache-2.0

tox.ini

@@ -60,6 +60,7 @@ commands = {posargs}
 [testenv:docs]
 deps =
   -c{env:TOX_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/victoria}
+  -r{toxinidir}/requirements.txt
   -r{toxinidir}/doc/requirements.txt
 commands =
     rm -rf doc/html doc/build