Improve error handling if no network available

[flubshi]

See: https://forum.kodi.tv/showthread.php?tid=365135

Log:

2021-11-03 08:32:50.506 T:7472    DEBUG <general>: AddOnLog: pvr.waipu: [login check] WAIPU.TV LOGIN...
2021-11-03 08:32:50.507 T:7472    DEBUG <general>: AddOnLog: pvr.waipu: [token] current time 1635924770
2021-11-03 08:32:50.507 T:7472    DEBUG <general>: AddOnLog: pvr.waipu: [token] expire  time 1635917196
2021-11-03 08:32:50.507 T:7472    DEBUG <general>: AddOnLog: pvr.waipu: [jwt isExpired] exp: 1635917196
2021-11-03 08:32:50.507 T:7472    DEBUG <general>: AddOnLog: pvr.waipu: [jwt isExpired] curr: 1635924770
2021-11-03 08:32:50.507 T:7472    DEBUG <general>: AddOnLog: pvr.waipu: [jwt isExpired] exp: 1646165692
2021-11-03 08:32:50.507 T:7472    DEBUG <general>: AddOnLog: pvr.waipu: [jwt isExpired] curr: 1635924770
2021-11-03 08:32:50.507 T:7472    DEBUG <general>: AddOnLog: pvr.waipu: [login check] Login-Request;
2021-11-03 08:32:50.507 T:7472    DEBUG <general>: AddOnLog: pvr.waipu: Http-Request: POST https://auth.waipu.tv/oauth/token.
2021-11-03 08:32:50.507 T:7472    DEBUG <general>: AddOnLog: pvr.waipu: Add cookies for host: auth.waipu.tv.
2021-11-03 08:32:50.507 T:7472    DEBUG <general>: CurlFile::ParseAndCorrectUrl() adding custom header option 'Authorization: ***********'
2021-11-03 08:32:50.507 T:7472    DEBUG <general>: CurlFile::ParseAndCorrectUrl() adding custom header option 'Content-Type: application/x-www-form-urlencoded'
2021-11-03 08:32:50.507 T:7472    DEBUG <general>: CurlFile::Open(0x25bdedb03c0) https://auth.waipu.tv/oauth/token
2021-11-03 08:32:50.517 T:7744    DEBUG <CSettingsManager>: requested setting (pvrmanager.enabled) was not found.
2021-11-03 08:32:50.517 T:7472    ERROR <general>: CCurlFile::FillBuffer - Failed: Couldn't connect to server(7)
2021-11-03 08:32:50.517 T:7472    ERROR <general>: CCurlFile::Open failed with code 0 for https://auth.waipu.tv/oauth/token:
                                                   
2021-11-03 08:32:50.517 T:7472    DEBUG <general>: AddOnLog: pvr.waipu: [login check] Login-response: (HTTP -1) ;
2021-11-03 08:32:50.517 T:7472    ERROR <general>: AddOnLog: pvr.waipu: [Login] no network connection
2021-11-03 08:32:50.517 T:7472    ERROR <general>: GetEPGForChannel: Add-on 'waipu.tv PVR add-on:connected' returned an error: server error
2021-11-03 08:32:50.517 T:7472    ERROR <general>: PVR::CPVREpg::Update: Failed to update table 'SR'
2021-11-03 08:32:50.525 T:7472    ERROR <general>: AddOnLog: pvr.waipu: [API LOGIN] Locked due to invalid attempts