sanity: exclude boards for samples/net/test_15_4

Excluded Quark D2000, Nucleo F103RB, Olimexino STM32 for the
sample test_15_4. Boards doesn't have support for 15.4 neither
enough space.

JIRA: ZEP-738
Change-Id: I963509a77cdf6a8ff2efee2f2d4a498e3c07f9b5
Signed-off-by: Javier B Perez <[email protected]>

Author: Javier B Perez

samples/net/test_15_4/testcase.ini

@@ -1,4 +1,4 @@
 [test]
 tags = net
-platform_exclude = arduino_101_sss quark_se_sss_devboard
+platform_exclude = arduino_101_sss quark_se_sss_devboard quark_d2000_crb nucleo_f103rb olimexino_stm32
 build_only = true