fix docker build-image

Change-Id: I7162d22c0003fa7a8d19011d4ac92882a9e0bdda
diff --git a/build-debian-packages-telegraf.groovy b/build-debian-packages-telegraf.groovy
index 2e4d71a..99839d6 100644
--- a/build-debian-packages-telegraf.groovy
+++ b/build-debian-packages-telegraf.groovy
@@ -42,7 +42,7 @@
                         "--build-arg uid=${jenkinsUID}",
                         "--build-arg timestamp=${timestamp}",
                         "-f ${workingDir}/telegraf/docker/${OS}-${DIST}-${ARCH}.Dockerfile",
-                        "docker"
+                        "."
                     ].join(' ')
                 )
             }