Use Linux Hosted Pool (#51)

build/devops_gated.yml

@@ -181,9 +181,9 @@ jobs:
       workingFolder: 'build_x86'
 
 - job: linuxubuntu
-  displayName: 'Build Linux Ubuntu 18.04'
+  displayName: 'Build Linux Ubuntu'
   pool:
-    name: Azure-MessagingStore
+    name: Azure-MessagingStore-LinuxBuildMachinePool
     demands:
     - linux
 
@@ -323,7 +323,7 @@ jobs:
 
 - job: includecheck_linux
   pool:
-    name: Azure-MessagingStore
+    name: Azure-MessagingStore-LinuxBuildMachinePool
     demands:
       - linux