Exec NewReportingPlugin must not error

[rstout]

Motivation

Previously, any single error during the call to NewReportingPlugin for the Exec plugin would cause the OCR instance to not start. Even if the error was transient and would be resolved if NewReportingPlugin was called again, the OCR instance would remain down.

Solution

In order to be robust to transient errors, NewReportingPlugin is retried until it succeeds.