Fix number of documents generated using the random importer

INFO : 1505 docs created
INFO : average speed = 0.5725104808807373 docs/s
INFO : immediate speed = 3.31564998626709 docs/s
INFO : All Threads terminated
INFO : 1505 docs created
INFO : 0.5725105 docs/s
INFO : Nuxeo-Importer-3-T11 --> 0
INFO : Nuxeo-Importer-3-T10 --> 0
INFO : Nuxeo-Importer-3-T13 --> 0
INFO : Nuxeo-Importer-3-T12 --> 0
INFO : Nuxeo-Importer-3-T15 --> 0
INFO : Nuxeo-Importer-3-T14 --> 0
INFO : Nuxeo-Importer-3-T16 --> 0
INFO : Nuxeo-Importer-4-T17 --> 0
INFO : Nuxeo-Importer-3-T18 --> 0
INFO : Nuxeo-Importer-4-T20 --> 0
INFO : Nuxeo-Importer-1-T8 --> 101
INFO : Nuxeo-Importer-3-T9 --> 0
INFO : Nuxeo-Importer-1-T0 --> 103
INFO : Nuxeo-Importer-2-T1 --> 199
INFO : Nuxeo-Importer-5-T4 --> 475
INFO : Nuxeo-Importer-3-T2 --> 176
INFO : Nuxeo-Importer-4-T3 --> 134
INFO : Nuxeo-Importer-2-T19 --> 0
INFO : Nuxeo-Importer-3-T7 --> 105
INFO : Nuxeo-Importer-4-T6 --> 105
INFO : Nuxeo-Importer-1-T5 --> 107
INFO : Simon Stopwatch: [org.nuxeo.ecm.platform.importer.create_leaf INHERIT] total 38.6 s, counter 1462, max 259 ms, min 3.44 ms, mean 26.4 ms
INFO : Simon Stopwatch: [org.nuxeo.ecm.platform.importer.session_save INHERIT] total 8387 s, counter 165, max 556 s, min 5.80 ms, mean 50.8 s
INFO : Simon Stopwatch: [org.nuxeo.ecm.platform.importer.create_folder INHERIT] total 182 ms, counter 23, max 33.8 ms, min 1.23 ms, mean 7.90 ms
INFO : Simon Stopwatch: [org.nuxeo.ecm.platform.importer.node_get_children INHERIT] total 9.53 ms, counter 23, max 5.81 ms, min 6.22 us, mean 414 us