hoodselector: ensure deleting of all iw interfaces befor preparing mesh interfaces for testing in scanmode

for example:

root@ffnwDevBox:/# iwinfo 
client0   ESSID: "nordwest.freifunk.net"
          Access Point: 96:5D:71:A7:E6:F8
          Mode: Master  Channel: 6 (2.437 GHz)
          Tx-Power: 18 dBm  Link Quality: unknown/70
          Signal: unknown  Noise: -93 dBm
          Bit Rate: unknown
          Encryption: none
          Type: nl80211  HW Mode(s): 802.11bgn
          Hardware: unknown [Generic MAC80211]
          TX power offset: unknown
          Frequency offset: unknown
          Supports VAPs: yes  PHY name: phy0

ibss0     ESSID: "mesh.ffnw"
          Access Point: 02:CA:FF:EE:BA:BF
          Mode: Ad-Hoc  Channel: 6 (2.437 GHz)
          Tx-Power: 18 dBm  Link Quality: unknown/70
          Signal: unknown  Noise: -93 dBm
          Bit Rate: unknown
          Encryption: unknown
          Type: nl80211  HW Mode(s): 802.11bgn
          Hardware: unknown [Generic MAC80211]
          TX power offset: unknown
          Frequency offset: unknown
          Supports VAPs: yes  PHY name: phy0

mesh0     ESSID: unknown
          Access Point: 00:00:00:00:00:00
          Mode: Mesh Point  Channel: 6 (2.437 GHz)
          Tx-Power: 18 dBm  Link Quality: unknown/70
          Signal: unknown  Noise: -93 dBm
          Bit Rate: unknown
          Encryption: unknown
          Type: nl80211  HW Mode(s): 802.11bgn
          Hardware: unknown [Generic MAC80211]
          TX power offset: unknown
          Frequency offset: unknown
          Supports VAPs: yes  PHY name: phy0

wlan0-3   ESSID: "foobar"
          Access Point: 96:5D:71:A7:E6:FB
          Mode: Master  Channel: 6 (2.437 GHz)
          Tx-Power: 18 dBm  Link Quality: unknown/70
          Signal: unknown  Noise: -93 dBm
          Bit Rate: unknown
          Encryption: WPA2 PSK (CCMP)
          Type: nl80211  HW Mode(s): 802.11bgn
          Hardware: unknown [Generic MAC80211]
          TX power offset: unknown
          Frequency offset: unknown
          Supports VAPs: yes  PHY name: phy0

root@ffnwDevBox:/#

In the above example there are more than the client0 network defined. Than the iw command runs in the case of trying using business resources.

root@ffnwDevBox:/# hoodselector
No VPN connection found
Testing neighboring adhoc networks for batman advanced gw connection.
The following wireless networks have been found:
0	2437	02:CA:FF:EE:BA:BF	mesh.ffnw
63	2437	02:00:0A:12:D0:00	mesh.ffnw
After filtering we will test the following wireless networks:
63	2437	02:00:0A:12:D0:00	mesh.ffnw
Prepare configuration for testing wireless networks...
VPN stopped.
Testing IBSS 02:00:0A:12:D0:00...
command failed: Device or resource busy (-16)
VPN started.
Interface br-client restarted.
Wireless restarted.
Finished testing wireless networks, restored previous configuration
No neighboring freifunk batman advanced mesh found.
Set hood "default"
Set defaulthood.
Interface mesh_wan enabled.
root@ffnwDevBox:/#