cleanup .build directory prior to build

Signed-off-by: Mike Marchetti <mmarchetti@sandvine.com>
diff --git a/Jenkinsfile b/Jenkinsfile
index f6f9a71..7caef74 100644
--- a/Jenkinsfile
+++ b/Jenkinsfile
@@ -8,6 +8,7 @@
 				dockerfile true
 			}
 			steps {
+				sh 'rm -rf .build'
 				sh 'make NOT_DEVELOPER_BUILD=TRUE -j16 package'
 				stash name: "deb-files", includes: ".build/*.deb"
 			}