Remove RTOS tests from Travis for DISCO_L072CZ_LRWAN1

Author: bulislaw

tools/build_travis.py

@@ -241,8 +241,7 @@
     {"target": "DISCO_L072CZ_LRWAN1",
      "toolchains": "GCC_ARM",
      "tests": {""     : ["MBED_2", "MBED_10", "MBED_11", "MBED_16"],
-               "rtos" : ["RTOS_1", "RTOS_2", "RTOS_3"],
-             }
+              }
     },
     {"target": "NUMAKER_PFM_NUC472",
      "toolchains": "GCC_ARM",