Fixed partitionIds type in EventHub

[mcardosos]

Based on documentation here.
This should fix this bug in the Go SDK.
@sazeesha @jhendrixMSFT

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This change is

[sazeesha]

@mcardosos this change looks good.

[mcardosos]

@amarzavery Can we merge this?

[amarzavery]

@lmazuel
The CI is failing for python. Can you take a look ?

mono /tmp/tmp9oxm94qm/autorest/tools/AutoRest.exe -i /git-restapi/arm-eventhub/2015-08-01/swagger/EventHub.json -o /tmp/tmp9oxm94qm/EventHub.json -AddCredentials True -CodeGenerator Azure.Python -Header MICROSOFT_MIT_NO_VERSION -Namespace azure.mgmt.eventhub -PackageVersion 0.1.0 -ft 2
ERROR:__main__:Command '['mono', '/tmp/tmp9oxm94qm/autorest/tools/AutoRest.exe', '-i', '/git-restapi/arm-eventhub/2015-08-01/swagger/EventHub.json', '-o', '/tmp/tmp9oxm94qm/EventHub.json', '-AddCredentials', 'True', '-CodeGenerator', 'Azure.Python', '-Header', 'MICROSOFT_MIT_NO_VERSION', '-Namespace', 'azure.mgmt.eventhub', '-PackageVersion', '0.1.0', '-ft', '2']' returned non-zero exit status 1
ERROR:__main__:Code generation failed.
AutoRest.exe -i /git-restapi/arm-eventhub/2015-08-01/swagger/EventHub.json -o /tmp/tmp9oxm94qm/EventHub.json -AddCredentials True -CodeGenerator Azure.Python -Header MICROSOFT_MIT_NO_VERSION -Namespace azure.mgmt.eventhub -PackageVersion 0.1.0 -ft 2
FATAL: Error loading Azure.Python assembly: Could not load file or assembly 'AutoRest.Python.Azure.dll' or one of its dependencies

Traceback (most recent call last):
  File "/SwaggerToSdk.py", line 631, in <module>
    main()
  File "/SwaggerToSdk.py", line 628, in main
    args.autorest_dir)
  File "/SwaggerToSdk.py", line 544, in build_libraries
    autorest_exe_path, global_conf, local_conf)
  File "/SwaggerToSdk.py", line 162, in generate_code
    cwd=str(swagger_path))
  File "/usr/lib/python3.4/subprocess.py", line 620, in check_output
    raise CalledProcessError(retcode, process.args, output=output)
subprocess.CalledProcessError: Command '['mono', '/tmp/tmp9oxm94qm/autorest/tools/AutoRest.exe', '-i', '/git-restapi/arm-eventhub/2015-08-01/swagger/EventHub.json', '-o', '/tmp/tmp9oxm94qm/EventHub.json', '-AddCredentials', 'True', '-CodeGenerator', 'Azure.Python', '-Header', 'MICROSOFT_MIT_NO_VERSION', '-Namespace', 'azure.mgmt.eventhub', '-PackageVersion', '0.1.0', '-ft', '2']' returned non-zero exit status 1

[mcardosos]

I think @fearthecowboy knows what's happening

[AutorestCI]

Azure/azure-sdk-for-ruby#515

[AutorestCI]

Azure/azure-sdk-for-node#1942

[AutorestCI]

Azure/azure-sdk-for-python#825