Support multiple users running robot tests

You can use robot with jenkins.  What I saw was the argument file was
explictly written to /tmp.  The Jenkins is a different user then my
user id so when Jenkins owned the /tmp/argument_file.txt my user id
trying to do things manually got a file permission error... and
visa versa.  So I am moving the argument_file.txt to a location
based off of the workspace where the test is being executed.
That allows multiple users on the same system to run the suite.

Change-Id: I81525c7f20708dbd24d219c8424cad59144ba4ab
Signed-off-by: Chris Austen <austenc@us.ibm.com>
diff --git a/.gitignore b/.gitignore
index eb901c8..dd86f44 100644
--- a/.gitignore
+++ b/.gitignore
@@ -3,4 +3,5 @@
 /output.xml
 /report.html
 /.idea/
-/.tox/
\ No newline at end of file
+/.tox/
+/tools/argument_file.txt
\ No newline at end of file