view: fix runDiagnostic output display

[shwstppr]

Fixes: #293

[rohityadavcloud]

@shwstppr the output should also show stderr and exit value like old UI:

exitcode: 0

stderr:

stdout: PING 8.8.8.8 (8.8.8.8): 56 data bytes 64 bytes from 8.8.8.8: icmp_seq=0 ttl=50 time=7.575 ms 64 bytes from 8.8.8.8: icmp_seq=1 ttl=50 time=8.030 ms 64 bytes from 8.8.8.8: icmp_seq=2 ttl=50 time=14.950 ms 64 bytes from 8.8.8.8: icmp_seq=3 ttl=50 time=7.617 ms --- 8.8.8.8 ping statistics --- 4 packets transmitted, 4 packets received, 0% packet loss round-trip min/avg/max/stddev = 7.575/9.543/14.950/3.127 ms

Side-note I'm getting network error, for some reason the API request fails that I couldn't debug - are you seeing this as well (when using a non-local mgmt server env):

[shwstppr]

@rhtyd it works with a lab env and also with cloudmonkey local env
Made changes to show stderr and errorCode,

[rohityadavcloud]

@shwstppr please follow the changes in future/related PRs

[shwstppr]

@rhtyd I'll ask before making changes in future/related PRs