Rename Robot Framework sources to *.robot

It avoids mixing robot and txt suffixes in the same directory.

Change-Id: Ia2288cc9ad7dc86fc9a4cea2c6ca7a08a7dd3e3c
Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>

diff --git a/testcases/Controllers/ODL/custom_tests/neutron/040__delete_ports.txt b/testcases/Controllers/ODL/custom_tests/neutron/040__delete_ports.robot
similarity index 100%
rename from testcases/Controllers/ODL/custom_tests/neutron/040__delete_ports.txt
rename to testcases/Controllers/ODL/custom_tests/neutron/040__delete_ports.robot

diff --git a/testcases/Controllers/ODL/custom_tests/neutron/050__delete_subnets.txt b/testcases/Controllers/ODL/custom_tests/neutron/050__delete_subnets.robot
similarity index 100%
rename from testcases/Controllers/ODL/custom_tests/neutron/050__delete_subnets.txt
rename to testcases/Controllers/ODL/custom_tests/neutron/050__delete_subnets.robot

diff --git a/testcases/Controllers/ODL/custom_tests/neutron/060__delete_networks.txt b/testcases/Controllers/ODL/custom_tests/neutron/060__delete_networks.robot
similarity index 100%
rename from testcases/Controllers/ODL/custom_tests/neutron/060__delete_networks.txt
rename to testcases/Controllers/ODL/custom_tests/neutron/060__delete_networks.robot