Restore CentOS on Power in CI.

shippable.yml

@@ -41,6 +41,7 @@ matrix:
     - env: T=linux/opensuse15/1
     - env: T=linux/ubuntu1604/1
     - env: T=linux/ubuntu1804/1
+    - env: T=power/centos/7/1
 
     - env: T=osx/10.11/2
     - env: T=rhel/7.8/2
@@ -56,6 +57,7 @@ matrix:
     - env: T=linux/opensuse15/2
     - env: T=linux/ubuntu1604/2
     - env: T=linux/ubuntu1804/2
+    - env: T=power/centos/7/2
 
     - env: T=osx/10.11/3
     - env: T=rhel/7.8/3
@@ -71,6 +73,7 @@ matrix:
     - env: T=linux/opensuse15/3
     - env: T=linux/ubuntu1604/3
     - env: T=linux/ubuntu1804/3
+    - env: T=power/centos/7/3
 
     - env: T=osx/10.11/4
     - env: T=rhel/7.8/4
@@ -86,6 +89,7 @@ matrix:
     - env: T=linux/opensuse15/4
     - env: T=linux/ubuntu1604/4
     - env: T=linux/ubuntu1804/4
+    - env: T=power/centos/7/4
 
     - env: T=osx/10.11/5
     - env: T=rhel/7.8/5
@@ -101,6 +105,7 @@ matrix:
     - env: T=linux/opensuse15/5
     - env: T=linux/ubuntu1604/5
     - env: T=linux/ubuntu1804/5
+    - env: T=power/centos/7/5
 
     - env: T=fallaxy/2.7/1
     - env: T=fallaxy/3.6/1
@@ -119,6 +124,7 @@ matrix:
     - env: T=i/linux/opensuse15
     - env: T=i/linux/ubuntu1604
     - env: T=i/linux/ubuntu1804
+    - env: T=i/power/centos/7
 
     - env: T=i/windows/2012
     - env: T=i/windows/2012-R2