MOBILE-1753 filepool: Fix race condition in _removeFileById
MOBILE-1753 filepool: Fix race condition in _removeFileById

bmmg888/moodlemobile2,mohitsofat/mobiskool,beppinu/moodleapp,mohitsofat/mobiskool,NEEDS-SAL/SOrCEv3,bmmg888/moodlemobile2,knurmi/MoodleTest,chester666/moodlemobile,balirwa/logs,balirwa/logs,salauddinias/jai-hind-app,romit19/SOrCEv3,romit19/SOrCEv3,GonzaloPachecoAlvarez/appteoloyu,NEEDS-SAL/SOrCEv3,balirwa/logs,NEEDS-SAL/SOrCEv3,dpaloucva/moodlemobile2,salauddinias/jai-hind-app,Andydadra/moodlemobile2,mvvkiev/moodlemobile2,arahimahmad/moodlemobile2,NEEDS-SAL/SOrCEv3,beppinu/moodleapp,knurmi/MoodleTest,SathvikEdla/SathvikApp,dougrosa/eadinatel,Andydadra/moodlemobile2,sulzer/moodlemobile2,GonzaloPachecoAlvarez/appteoloyu,jnguy054/moodlemobile2,testvibid/imaritime,romit19/SOrCEv3,sulzer/moodlemobile2,bmmg888/moodlemobile2,balirwa/logs,MUPC-GH/MillikinMobileMoodle2,chester666/moodlemobile,SathvikEdla/SathvikApp,brenda10campos/GACER1,MUPC-GH/MobileMoodle3.2.0,dougrosa/eadinatel,NEEDS-SAL/SOrCEv3,brenda10campos/GACER1,testvibid/imaritime,balirwa/logs,MUPC-GH/MillikinMobileMoodle2,romit19/SOrCEv3,digidoug/fsdmoodle,mohitsofat/mobiskool,bmmg888/moodlemobile2,MUPC-GH/MobileMoodle3.2.0,balirwa/logs,chester666/moodlemobile,mvvkiev/moodlemobile2,marceloalmeidasousa/moodleapp,sulzer/moodlemobile2,4emunoz/avcolsub,Diaa75/moodlemobile2,marceloalmeidasousa/moodleapp,digidoug/fsdmoodle,dpaloucva/moodlemobile2,Diaa75/moodlemobile2,jnguy054/moodlemobile2,NEEDS-SAL/SOrCEv3,arahimahmad/moodlemobile2,arahimahmad/moodlemobile2,4emunoz/avcolsub,romit19/SOrCEv3,romit19/SOrCEv3