UnhandledException not cleared when Interceptor handles exception

[lawley]

In the RestfulServer there are two places (lines 1220 and 1282) where the Pointcut.SERVER_HANDLE_EXCEPTION interceptor is called and if it returns false (signifying that the exception has been "handled"), the handleRequest method then returns.

However, it doesn't clear the variable unhandledException before doing so which means the finally block then attempts to (re-)handle the exception. This can result it another exception being thrown as a second attempt is made to write an output result.

I believe the fix is to add:

`unhandledException = null;`

before each of these return statements.

[jgsuess]

hapi-fhir/hapi-fhir-server/src/main/java/ca/uhn/fhir/rest/server/RestfulServer.java

Line 1220 in bbff855

return;

hapi-fhir/hapi-fhir-server/src/main/java/ca/uhn/fhir/rest/server/RestfulServer.java

Line 1282 in bbff855

return;

Handling:

hapi-fhir/hapi-fhir-server/src/main/java/ca/uhn/fhir/rest/server/RestfulServer.java

Line 1300 in bbff855

if (unhandledException != null) {