Ensure func->functional tox env mapping works

Currently the mapping of the 'functional' to the 'func'
tox environments does not work for Ubuntu Xenial. This
is due to the shell not being set, and the default shell
somehow being 'dash' instead of 'bash'.

This ensures that the shell is properly set for all shell
tasks, but also makes this mapping optional. If the
'functional' tox env is present it will be used - otherwise
it will use the 'func' tox env. This allows all these jobs
to transition if they wish.

Change-Id: Id63e626fd34f9c2ebb89dfae8fdda936a1ecfdf5

playbooks/legacy/ansible-func/run.yaml

@@ -55,6 +55,7 @@
             sudo yum-config-manager --enable updates >/dev/null
           fi
         chdir: '{{ ansible_user_dir }}/workspace'
+        executable: /bin/bash
       environment: '{{ zuul | zuul_legacy_vars }}'
 
     - shell:
@@ -72,6 +73,7 @@
             sudo yum-config-manager --disable epel >/dev/null
           fi
         chdir: '{{ ansible_user_dir }}/workspace'
+        executable: /bin/bash
       environment: '{{ zuul | zuul_legacy_vars }}'
 
     - shell:
@@ -82,6 +84,7 @@
           ssh-keyscan localhost >> ~/.ssh/known_hosts
           ssh-keyscan 127.0.0.1 >> ~/.ssh/known_hosts
         chdir: '{{ ansible_user_dir }}/workspace'
+        executable: /bin/bash
       environment: '{{ zuul | zuul_legacy_vars }}'
 
     - shell:
@@ -90,11 +93,13 @@
           # called 'functional', so we implement a mapping
           # of the scenario 'func' to 'functional' so reduce
           # the need for code churn in those repositories
-          # immediately.
-          if [ "func" == "func" ]; then
+          # immediately. This mapping is only implemented
+          # if the tox environment 'functional' exists.
+          if grep -q functional tox.ini; then
             /usr/local/jenkins/slave_scripts/run-tox.sh functional
           else
             /usr/local/jenkins/slave_scripts/run-tox.sh func
           fi
         chdir: '{{ ansible_user_dir }}/workspace'
+        executable: /bin/bash
       environment: '{{ zuul | zuul_legacy_vars }}'