Login pattern was too restrictive for example for those using LDAP.
So even if there are limitations in the characters of ntopng usernames,
one can still use external login systems and be able to login with usernames
containing special characters.
Fixes#1884
Prevents
25/Jul/2018 13:18:19 [LuaEngine.cpp:4325] ERROR: Error 'opening '/var/tmp/ntopng/0/rrd/SSL.rrd': No such file or directory' while calling rrd_fetch_r(/var/tmp/ntopng/0/rrd/SSL.rrd, AVERAGE): is the RRD corrupted perhaps?
25/Jul/2018 13:18:19 [dashboard.lua:78] [rrd.lua:327] RRD driver does not support listSeries on multiple tags
25/Jul/2018 13:18:19 [LuaEngine.cpp:4325] ERROR: Error 'opening '/var/tmp/ntopng/0/rrd/HTTP.rrd': No such file or directory' while calling rrd_fetch_r(/var/tmp/ntopng/0/rrd/HTTP.rrd, AVERAGE): is the RRD corrupted perhaps?
25/Jul/2018 13:18:19 [dashboard.lua:78] [rrd.lua:327] RRD driver does not support listSeries on multiple tags
25/Jul/2018 13:18:19 [LuaEngine.cpp:4325] ERROR: Error 'opening '/var/tmp/ntopng/0/rrd/SSH.rrd': No such file or directory' while calling rrd_fetch_r(/var/tmp/ntopng/0/rrd/SSH.rrd, AVERAGE): is the RRD corrupted perhaps?
25/Jul/2018 13:18:19 [dashboard.lua:78] [rrd.lua:327] RRD driver does not support listSeries on multiple tags
25/Jul/2018 13:18:19 [LuaEngine.cpp:4325] ERROR: Error 'opening '/var/tmp/ntopng/0/rrd/Unknown.rrd': No such file or directory' while calling rrd_fetch_r(/var/tmp/ntopng/0/rrd/Unknown.rrd, AVERAGE): is the RRD corrupted perhaps?
25/Jul/2018 13:18:19 [dashboard.lua:78] [rrd.lua:327] RRD driver does not support listSeries on multiple tags
25/Jul/2018 13:18:19 [LuaEngine.cpp:4325] ERROR: Error 'opening '/var/tmp/ntopng/0/rrd/sFlow.rrd': No such file or directory' while calling rrd_fetch_r(/var/tmp/ntopng/0/rrd/sFlow.rrd, AVERAGE): is the RRD corrupted perhaps?
25/Jul/2018 13:18:19 [dashboard.lua:78] [rrd.lua:327] RRD driver does not support listSeries on multiple tags
25/Jul/2018 13:18:19 [LuaEngine.cpp:4325] ERROR: Error 'opening '/var/tmp/ntopng/0/rrd/DNS.rrd': No such file or directory' while calling rrd_fetch_r(/var/tmp/ntopng/0/rrd/DNS.rrd, AVERAGE): is the RRD corrupted perhaps?
25/Jul/2018 13:18:19 [dashboard.lua:78] [rrd.lua:327] RRD driver does not support listSeries on multiple tags
25/Jul/2018 13:18:19 [LuaEngine.cpp:4325] ERROR: Error 'opening '/var/tmp/ntopng/0/rrd/ICMP.rrd': No such file or directory' while calling rrd_fetch_r(/var/tmp/ntopng/0/rrd/ICMP.rrd, AVERAGE): is the RRD corrupted perhaps?
25/Jul/2018 13:18:19 [dashboard.lua:78] [rrd.lua:327] RRD driver does not support listSeries on multiple tags