Fix for WiFi.connecting() returning false during DHCP configuration

[sergeuz]

This PR fixes #1241 by making WLAN_CONNECTING and WLAN_CONNECTED flags span over the entire network connection process, including DHCP configuration phase.

I'm not sure how I can write a good test for this fix, so below is my usual test application which I play with to debug network/cloud connectivity problems. Make sure you build the system firmware with debugging enabled and DEBUG_NETWORK_STATE macro defined to get internal state of the ManagedNetworkInterface class logged.

Tested on Photon and Electron with static and dynamic IP configurations.

#include "application.h"

SYSTEM_MODE(MANUAL)
// SYSTEM_THREAD(ENABLED)

#if PLATFORM_ID == 10
#define Network Cellular
#else
#define Network WiFi
#endif

namespace {

Serial1LogHandler logHandler(115200, LOG_LEVEL_WARN, {
    { "system.network.state", LOG_LEVEL_ALL },
    { "app", LOG_LEVEL_ALL }
});

void connectionStatusChanged(system_event_t event, int data) {
    switch (event) {
    case network_status: {
        switch (data) {
        case network_status_powering_off: Log.info("network_status_powering_off"); break;
        case network_status_off: Log.info("network_status_off"); break;
        case network_status_powering_on: Log.info("network_status_powering_on"); break;
        case network_status_on: Log.info("network_status_on"); break;
        case network_status_connecting: Log.info("network_status_connecting"); break;
        case network_status_connected: Log.info("network_status_connected"); break;
        case network_status_disconnecting: Log.info("network_status_disconnecting"); break;
        case network_status_disconnected: Log.info("network_status_disconnected"); break;
        }
        Log.info(PP_STR(Network) ".connecting() == %d", (int)Network.connecting());
        Log.info(PP_STR(Network) ".ready() == %d", (int)Network.ready());
        break;
    }
    case cloud_status: {
        switch (data) {
        case cloud_status_disconnected: Log.info("cloud_status_disconnected"); break;
        case cloud_status_connecting: Log.info("cloud_status_connecting"); break;
        case cloud_status_connected: Log.info("cloud_status_connected"); break;
        case cloud_status_disconnecting: Log.info("cloud_status_disconnecting"); break;
        }
        Log.info("Particle.connected() == %d", (int)Particle.connected());
        break;
    }
    default:
        break;
    }
}

uint32_t t = 0;
int step = 0;

} // namespace

STARTUP(System.on(network_status | cloud_status, connectionStatusChanged))

void setup() {
/*
    WiFi.on();

    // Use static IP configuration
    IPAddress addr(192,168,1,177);
    IPAddress mask(255,255,255,0);
    IPAddress gateway(192,168,1,1);
    IPAddress dns(192,168,1,1);
    WiFi.setStaticIP(addr, mask, gateway, dns);
    WiFi.useStaticIP();

    // Use dynamic IP configuration
    WiFi.useDynamicIP();
*/
}

void loop() {
    if (step && millis() - t < 6000) {
        // Particle.process();
        return;
    }
    switch (++step) {
    case 1: {
        Log.info("-> " PP_STR(Network) ".on()");
        Network.on();
        break;
    }
    case 2: {
        Log.info("-> " PP_STR(Network) ".connect()");
        Network.connect();
        break;
    }
    case 3: {
        Log.info("-> Particle.connect()");
        Particle.connect();
        break;
    }
    case 4: {
        Log.info("-> Particle.disconnect()");
        Particle.disconnect();
        break;
    }
    case 5: {
        Log.info("-> " PP_STR(Network) ".disconnect()");
        Network.disconnect();
        break;
    }
    case 6: {
        Log.info("-> " PP_STR(Network) ".off()");
        Network.off();
        break;
    }
    default:
        break;
    }
    t = millis();
}

---

Doneness:

• Contributor has signed CLA
• Problem and Solution clearly stated
• Code peer reviewed
• API tests compiled
• Run unit/integration/application tests on device
• Add documentation (N/A)
• Add to CHANGELOG.md after merging (add links to docs and issues)

Bugfixes

• [PR #1254] [Fixes #1241] WiFi.connecting() was returning false while DHCP is resolving, will now remain true.