Fix Backup feature

[RafaelAPB]

Jun 13 15:00:00 gce-neiist app/web.1: error: uncaughtException: spawn mongoexport ENOENT date=Thu Jun 13 2019 22:00:00 GMT+0000 (Coordinated Universal Time), pid=36, uid=46595, gid=46595, cwd=/app, execPath=/app/.heroku/node/bin/node, version=v10.15.0, argv=[/app/.heroku/node/bin/node, /app/gce_base.js], rss=87138304, heapTotal=50065408, heapUsed=33628304, external=18354438, loadavg=[5.3525390625, 5.78076171875, 6.515625], uptime=309398, trace=[column=19, file=internal/child_process.js, function=Process.ChildProcess._handle.onexit, line=232, method=onexit, native=false, column=16, file=internal/child_process.js, function=onErrorNT, line=407, method=null, native=false, column=19, file=internal/process/next_tick.js, function=process._tickCallback, line=63, method=_tickCallback, native=false], stack=[Error: spawn mongoexport ENOENT, at Process.ChildProcess._handle.onexit (internal/child_process.js:232:19), at onErrorNT (internal/child_process.js:407:16), at process._tickCallback (internal/process/next_tick.js:63:19)]
Jun 13 15:00:00 gce-neiist app/web.1: error: uncaughtException: spawn mongoexport ENOENT date=Thu Jun 13 2019 22:00:00 GMT+0000 (Coordinated Universal Time), pid=36, uid=46595, gid=46595, cwd=/app, execPath=/app/.heroku/node/bin/node, version=v10.15.0, argv=[/app/.heroku/node/bin/node, /app/gce_base.js], rss=87482368, heapTotal=50065408, heapUsed=33768296, external=18354438, loadavg=[5.3525390625, 5.78076171875, 6.515625], uptime=309398, trace=[column=19, file=internal/child_process.js, function=Process.ChildProcess._handle.onexit, line=232, method=onexit, native=false, column=16, file=internal/child_process.js, function=onErrorNT, line=407, method=null, native=false, column=19, file=internal/process/next_tick.js, function=process._tickCallback, line=63, method=_tickCallback, native=false], stack=[Error: spawn mongoexport ENOENT, at Process.ChildProcess._handle.onexit (internal/child_process.js:232:19), at onErrorNT (internal/child_process.js:407:16), at process._tickCallback (internal/process/next_tick.js:63:19)]
Jun 13 15:00:00 gce-neiist app/web.1: Caught exception: Error: spawn mongoexport ENOENT
Jun 13 15:00:00 gce-neiist app/web.1: error: Process terminating:
Jun 13 15:00:00 gce-neiist app/web.1: error: Error: spawn mongoexport ENOENT
Jun 13 15:00:00 gce-neiist app/web.1: at onErrorNT (internal/child_process.js:407:16)
Jun 13 15:04:05 gce-neiist heroku/router: at=error code=H21 desc="Backend connection refused" method=GET path="/robots.txt" host=www.gce-neiist.org request_id=6cdffc90-58e0-41dc-8ec4-7ea81d7ac3a1 fwd="66.249.64.199" dyno=web.1 connect=0ms service= status=503 bytes= protocol=https