Skip building mqtt on centos 6

Author: Konstantin Nazarov

Jenkinsfile

@@ -1,8 +1,14 @@
 stage('Build'){
     packpack = new org.tarantool.packpack()
+
+    // No mosquitto library on centos 6
+    matrix = packpack.filterMatrix(
+        packpack.default_matrix,
+        {!(it['OS'] == 'centos' && it['DIST'] == '6')})
+
     node {
         checkout scm
         packpack.prepareSources()
     }
-    packpack.packpackBuildMatrix('result')
+    packpack.packpackBuildMatrix('result', matrix)
 }