Drop leftover of functional tests

Functional tests have been removed from core aodh repo and are now run
by telemetry-tempest-plugin.

Remove the remaining items kept in tox.ini.

Change-Id: I5458308efa1acacf3013c94053942dc6a314e71a

tox.ini

@@ -1,6 +1,6 @@
 [tox]
 minversion = 4.2.5
-envlist = py3{,-mysql,-postgresql},functional,pep8
+envlist = py3,pep8
 
 [testenv]
 usedevelop = False
@@ -9,16 +9,8 @@ setenv =
     OS_STDERR_CAPTURE=1
     OS_TEST_TIMEOUT=600
 
-    AODH_TEST_DRIVERS=postgresql mysql
-    mysql: AODH_TEST_DRIVERS=mysql
-    postgresql: AODH_TEST_DRIVERS=postgresql
-
-    AODH_TEST_DEPS=postgresql,mysql
-    mysql: AODH_TEST_DEPS=mysql
-    postgresql: AODH_TEST_DEPS=postgresql
 deps =
     -c{env:TOX_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master}
-    .[{env:AODH_TEST_DEPS}]
     -r{toxinidir}/test-requirements.txt
     -r{toxinidir}/requirements.txt
 passenv =
@@ -26,7 +18,6 @@ passenv =
     OS_STDOUT_CAPTURE
     OS_STDERR_CAPTURE
     OS_LOG_CAPTURE
-    AODH_TEST_DRIVERS
 commands =
     stestr --test-path=./aodh/tests run {posargs}
     aodh-config-generator