optimize size and time using "--no-cache-dir"

Using "--no-cache-dir" flag in pip install ,make sure dowloaded packages
by pip don't cached on system . This is a best practise which make sure
to fetch ftom repo instead of using local cached one . Further , in case
of Docker Containers , by restricing caching , we can reduce image size.
In term of stats , it depends upon the number of python packages
multiplied by their respective size . e.g for heavy packages with a lot
of dependencies it reduce a lot by don't caching pip packages.

Further , more detail information can be found at

https://medium.com/sciforce/strategies-of-docker-images-optimization-2ca9cc5719b6

Issue-ID: INT-1616

Signed-off-by: Pratik Raj <rajpratik71@gmail.com>
Change-Id: Id3e28faf35f36258362323b4a96bcf0f3f95726b
Signed-off-by: mrichomme <morgan.richomme@orange.com>
diff --git a/S3Ptools/locust_Grafana.sh b/S3Ptools/locust_Grafana.sh
index 5fa6fdc..5168f0e 100644
--- a/S3Ptools/locust_Grafana.sh
+++ b/S3Ptools/locust_Grafana.sh
@@ -1,7 +1,7 @@
 #!/bin/bash
 #grafana install for the use of locust
 # localgosh:80(grafana) & localhost:81
-pip install docker==3.1.4
+pip install --no-cache-dir docker==3.1.4
 git clone https://github.com/kamon-io/docker-grafana-graphite.git
 cd docker-grafana-graphite
 make up