Disable examples unsupported on spi feature branch.

mbed-os-example-sd-driver: on spi feature branch SD componen is disabled for K64F - disable this example.
mbed-os-example-bootloader: example is using SPI pins which are now undefined on NUCLEO_F429ZI - disable this example.

Author: mprse

tools/test/examples/examples.json

@@ -271,21 +271,6 @@
         "export": true,
         "auto-update" : true
     },
-    {
-        "name": "mbed-os-example-bootloader",
-        "github":"https://github.com/ARMmbed/mbed-os-example-bootloader",
-        "mbed": [
-            "https://os.mbed.com/teams/mbed-os-examples/code/mbed-os-example-bootloader"
-        ],
-        "test-repo-source": "github",
-        "features" : [],
-        "targets" : ["NUCLEO_F429ZI"],
-        "toolchains" : [],
-        "exporters": [],
-        "compile" : true,
-        "export": true,
-        "auto-update" : true
-    },
     {
         "name": "mbed-os-example-mbed-crypto",
         "github":"https://github.com/ARMmbed/mbed-os-example-mbed-crypto",
@@ -352,19 +337,6 @@
         "compile" : true,
         "export": true,
         "auto-update" : true
-    },
-    {
-        "name": "mbed-os-example-sd-driver",
-        "github":"https://github.com/ARMmbed/mbed-os-example-sd-driver",
-        "mbed": [],
-        "test-repo-source": "github",
-        "features" : [],
-        "targets" : ["K64F"],
-        "toolchains" : [],
-        "exporters": [],
-        "compile" : true,
-        "export": true,
-        "auto-update" : true
     }
   ]
 }