conf:Traffic-type naming convention and consistency

conf:Traffic-type naming convention and consistency

Following changes are added following first review
1. Descriptions in integration/01_testcases.conf
2. Comment in conf/01_testcases.conf
3. Checking all cases of traffic types in traffic_controller_rfc2544.py
4. Removing whitespaces
5. Missing changes (throughput->rfc2544_throughput)
6. Syntax error in core/traffic_controller_rfc2544.py

Currently the traffic-type values that are provided as part of the
test case definition needs some fix to support additional traffic
- apart from rfc2544. The Current and the proposed changed is summarized
in the below table:

|--------------------------------------------------------------------|
|  Parameter  | Existing traffic_type value |    Changed to          |
----------------------------------------------------------------------
| Throughput  | rfc2544  OR throughput      |   rfc2544_throughput   |
----------------------------------------------------------------------
| Back2Back   | back2back                   |   rfc2544_back2back    |
----------------------------------------------------------------------
| Continuous  | continuous                  |   rfc2544_continuous   |
----------------------------------------------------------------------

JIRA: VSPERF-420

Change-Id: I22bd897f6389d2b568a6a3735c67f0003e813445
Signed-off-by: Sridhar K. N. Rao <sridhar.rao@spirent.com>