Use lower default value for sha512_crypt rounds
Use lower default value for sha512_crypt rounds

Change Ia7c359df0d2f846a16b9fb98937f2995e9791010 rasied the issue of
hashes taking too long.  Upon investigation the default hasn't changed
since the original commit Idd5d09dc114cbb0cbd63e23e4178bb74d081c789

passlib's default comes with the rationale:

 Passlib’s default_rounds values are retuned periodically, starting
 with a rough estimate of what an “average” system is capable of, and
 then setting all hash.default_rounds values to take ~300ms on such a
 system. [1]

Presumably at the time of creation passlib defined the default as
40000 and that was copied here.  It is now 100000, and grows to keep
their 300ms target.

Both values exceed the glibc default of 5000 [2]. Based upon benchmarks
the reduction from 40000 to 10000 resulted in a net savings of ~30%. The
10000 round mark still exceeds the glibc default.

[1] https://pythonhosted.org/passlib/password_hash_api.html#avgsys
[2] https://sourceware.org/git/?p=glibc.git;a=blob;f=crypt/sha512-crypt.c;h=9c581abb00eb93ba6b0571c08e01fc65f1b1cd05;hb=HEAD#l87

Change-Id: I4bd7ef633070159b81c5e5d6d75275d63f976d28

vivekdhayaal/keystone,mahak/keystone,ilay09/keystone,dims/keystone,roopali8/keystone,klmitch/keystone,ilay09/keystone,vivekdhayaal/keystone,mahak/keystone,maestro-hybrid-cloud/keystone,jamielennox/keystone,idjaw/keystone,mahak/keystone,maestro-hybrid-cloud/keystone,roopali8/keystone,jonnary/keystone,idjaw/keystone,himanshu-setia/keystone,himanshu-setia/keystone,jamielennox/keystone,ilay09/keystone,ajayaa/keystone,rajalokan/keystone,openstack/keystone,jonnary/keystone,cernops/keystone,cernops/keystone,openstack/keystone,dstanek/keystone,rajalokan/keystone,klmitch/keystone,dstanek/keystone,dims/keystone,rajalokan/keystone,vivekdhayaal/keystone,ajayaa/keystone,takeshineshiro/keystone,dstanek/keystone,takeshineshiro/keystone,openstack/keystone