[goal] Migrate testing to ubuntu focal

As per victoria cycle testing runtime and community goal[1]
we need to migrate upstream CI/CD to Ubuntu Focal(20.04).

Fixing:
- bug#1885825
Fix user creation with GRANT in MySQL 8.0(Ubuntu Focal)
Ubuntu Focal (20.04) has mysql 8.0 and with mysql 8.0 there
is no implicit user creation with GRANT. We need to
create the user first before using GRANT command.

Story: #2007865
Task: #40196

Closes-Bug: #1885825

[1] https://governance.openstack.org/tc/goals/selected/victoria/migrate-ci-cd-jobs-to-ubuntu-focal>

Change-Id: Idb053c8b1bfde9870eea80f66e5aef156422a668

lower-constraints.txt

@@ -5,7 +5,7 @@ coverage==4.0
 croniter==0.3.4
 doc8==0.6.0
 dogpile.cache==0.6.2
-eventlet==0.20.0
+eventlet==0.26.0
 fixtures==3.0.0
 Jinja2==2.10
 jsonschema==3.2.0

requirements.txt

@@ -7,7 +7,7 @@ Babel!=2.4.0,>=2.3.4 # BSD
 croniter>=0.3.4 # MIT License
 cachetools>=2.0.0 # MIT License
 dogpile.cache>=0.6.2 # BSD
-eventlet!=0.20.1,!=0.21.0,!=0.23.0,!=0.25.0,>=0.20.0 # MIT
+eventlet>=0.26.0 # MIT
 Jinja2>=2.10 # BSD License (3 clause)
 jsonschema>=3.2.0 # MIT
 keystonemiddleware>=4.18.0 # Apache-2.0

tools/test-setup.sh

@@ -23,8 +23,8 @@ sudo -H mysqladmin -u root password $DB_ROOT_PW
 sudo -H mysql -u root -p$DB_ROOT_PW -h localhost -e "
     DELETE FROM mysql.user WHERE User='';
     FLUSH PRIVILEGES;
-    GRANT ALL PRIVILEGES ON *.*
-        TO '$DB_USER'@'%' identified by '$DB_PW' WITH GRANT OPTION;"
+    CREATE USER '$DB_USER'@'%' IDENTIFIED BY '$DB_PW';
+    GRANT ALL PRIVILEGES ON *.* TO '$DB_USER'@'%' WITH GRANT OPTION;"
 
 # Now create our database.
 mysql -u $DB_USER -p$DB_PW -h 127.0.0.1 -e "