fix compile warning
fix compile warning

graetzer/arangodb,wiltonlazary/arangodb,Simran-B/arangodb,Simran-B/arangodb,graetzer/arangodb,graetzer/arangodb,arangodb/arangodb,wiltonlazary/arangodb,wiltonlazary/arangodb,Simran-B/arangodb,graetzer/arangodb,Simran-B/arangodb,arangodb/arangodb,graetzer/arangodb,arangodb/arangodb,graetzer/arangodb,graetzer/arangodb,graetzer/arangodb,graetzer/arangodb,Simran-B/arangodb,graetzer/arangodb,graetzer/arangodb,Simran-B/arangodb,wiltonlazary/arangodb,Simran-B/arangodb,arangodb/arangodb,arangodb/arangodb,arangodb/arangodb,wiltonlazary/arangodb,Simran-B/arangodb,arangodb/arangodb,wiltonlazary/arangodb,Simran-B/arangodb,graetzer/arangodb,wiltonlazary/arangodb,graetzer/arangodb,Simran-B/arangodb,graetzer/arangodb,arangodb/arangodb,wiltonlazary/arangodb