Require python-ironicclient>=2.7.0

This is related to change I5f78d21c39ed2fd58d2a0f3649116e39883d5a2c
which depends on python-ironicclient change
I610836e5038774621690aca88b2aee25670f0262 which was released in
2.7.0. The former did not have a direct dependency or version
bump since it is being backported to stable branches where we
don't bump minimum required versions of dependencies.

Change-Id: I5edf350b29ef3bd1f103cdd4b0b997cb5ca32117
Related-Bug: #1818295

Author: mriedem

lower-constraints.txt

@@ -129,7 +129,7 @@ python-cinderclient==3.3.0
 python-dateutil==2.5.3
 python-editor==1.0.3
 python-glanceclient==2.8.0
-python-ironicclient==2.4.0
+python-ironicclient==2.7.0
 python-keystoneclient==3.15.0
 python-mimeparse==1.6.0
 python-neutronclient==6.7.0

test-requirements.txt

@@ -11,7 +11,7 @@ mox3>=0.20.0 # Apache-2.0
 psycopg2>=2.6.2 # LGPL/ZPL
 PyMySQL>=0.7.6 # MIT License
 python-barbicanclient>=4.5.2 # Apache-2.0
-python-ironicclient>=2.4.0 # Apache-2.0
+python-ironicclient>=2.7.0 # Apache-2.0
 requests-mock>=1.2.0 # Apache-2.0
 oslotest>=3.2.0 # Apache-2.0
 stestr>=1.0.0 # Apache-2.0