Bump os-traits to latest 2.6.0

The latest os-traits release introduced 3 new standard traits

While bumping the os-traits requirements it turned out that the
lower-constraints become extra slow causing a timeout. This result is a
catch-22 situation. The lower-constraint job cannot be fixed alone as
the global requirement bump already happened for os-traits 2.6.0
requiring fixing the placement tests. But fixing the placement tests
alone is not possible as the lower-constraints job will time out.

So this patch squashes in Icd0a304fc989c9535db125cd483ecac92deb011d:

Pip is slow to resolve version constraints with many unrestricted
dependencies. The recent slowness seems to be due to amqp is being
unrestricted and pip starts with amqp 5.0.3 but the real minimum is
somewhere around amqp 2.5.0. This patch adds amqp 2.5.0 to
lower-constraints to speed up the pip version resolution.

Change-Id: I89b330d0647b0883eecaf40b988a1a4779bcb1dd

lower-constraints.txt

@@ -1,4 +1,6 @@
 alembic==0.9.8
+# only need to speed up the pip version resolution
+amqp==2.5.0
 appdirs==1.4.3
 attrs==17.4.0
 bandit==1.1.0
@@ -34,7 +36,7 @@ netifaces==0.10.4
 os-client-config==1.29.0
 os-resource-classes==1.1.0
 os-service-types==1.2.0
-os-traits==2.5.0
+os-traits==2.6.0
 oslo.concurrency==3.26.0
 oslo.config==6.7.0
 oslo.context==2.22.0

placement/tests/functional/gabbits/traits.yaml

@@ -12,7 +12,7 @@ tests:
 - name: what is at traits
   GET: /traits
   response_json_paths:
-      $.traits.`len`: 291  #  Number of standard traits
+      $.traits.`len`: 294  #  Number of standard traits
 
 - name: create a trait without custom namespace
   PUT: /traits/TRAIT_X

requirements.txt

@@ -22,5 +22,5 @@ oslo.middleware>=3.31.0 # Apache-2.0
 oslo.upgradecheck>=1.3.0 # Apache-2.0
 # NOTE(efried): Sync lower-constraints.txt for os-traits & os-resource-classes.
 os-resource-classes>=1.1.0 # Apache-2.0
-os-traits>=2.5.0 # Apache-2.0
+os-traits>=2.6.0 # Apache-2.0
 microversion-parse>=0.2.1 # Apache-2.0