tw_cli: handle VERIFYING state on disks as rebuilding not failure

Before:

```
CRITICAL: mdstat:[md127(2.73 TiB):, md3(445.91 GiB raid1):UU, md0(1023.94 MiB raid1):UU, md2(99.99 MiB raid1):UU]; tw_cli:[c0(9750-4i): u1(RAID-6): VERIFYING 16%(A), Cache:RiW, c0(9750-4i): u2(SPARE): VERIFYING 13%, c0(9750-4i): u0(RAID-6): VERIFYING 26%(A), Cache:RiW, c0(9750-4i): u3(SPARE): VERIFYING 0%, Drives(18): p10,p11,p12,p13,p14,p15,p16,p17,p18,p19,p20,p21,p22,p23,p24,p8=OK p25,p9=VERIFYING]
```

After:

```
WARNING: mdstat:[md127(2.73 TiB):, md3(445.91 GiB raid1):UU, md0(1023.94 MiB raid1):UU, md2(99.99 MiB raid1):UU]; tw_cli:[c0(9750-4i): u1(RAID-6): VERIFYING 16%(A), Cache:RiW, c0(9750-4i): u3(SPARE): VERIFYING 0%, c0(9750-4i): u2(SPARE): VERIFYING 13%, c0(9750-4i): u0(RAID-6): VERIFYING 27%(A), Cache:RiW, Drives(18): p10,p11,p12,p13,p14,p15,p16,p17,p18,p19,p20,p21,p22,p23,p24,p8=OK p25,p9=VERIFYING]
```

This corresponds to:

```

VPort Status         Unit Size      Type  Phy Encl-Slot    Model
------------------------------------------------------------------------------
p8    OK             u0   2.73 TB   SATA  -   /c0/e0/slt0  ST3000NC002-1DY166
p9    VERIFYING      u3   2.73 TB   SATA  -   /c0/e0/slt1  ST3000NC002-1DY166
p10   OK             u0   2.73 TB   SATA  -   /c0/e0/slt2  ST3000NC002-1DY166
p11   OK             u0   2.73 TB   SATA  -   /c0/e0/slt3  ST3000NC002-1DY166
p12   OK             u0   2.73 TB   SATA  -   /c0/e0/slt4  ST3000NC002-1DY166
p13   OK             u0   2.73 TB   SATA  -   /c0/e0/slt5  ST3000NC002-1DY166
p14   OK             u0   2.73 TB   SATA  -   /c0/e0/slt6  ST3000NC002-1DY166
p15   OK             u0   2.73 TB   SATA  -   /c0/e0/slt7  ST3000NC002-1DY166
p16   OK             u1   2.73 TB   SATA  -   /c0/e0/slt8  ST3000NC002-1DY166
p17   OK             u1   2.73 TB   SATA  -   /c0/e0/slt9  ST3000NC002-1DY166
p18   OK             u1   2.73 TB   SATA  -   /c0/e0/slt10 ST3000NC002-1DY166
p19   OK             u1   2.73 TB   SATA  -   /c0/e0/slt11 ST3000NC002-1DY166
p20   OK             u1   2.73 TB   SATA  -   /c0/e0/slt12 ST3000NC002-1DY166
p21   OK             u1   2.73 TB   SATA  -   /c0/e0/slt13 ST3000NC002-1DY166
p22   OK             u1   2.73 TB   SATA  -   /c0/e0/slt14 ST3000NC002-1DY166
p23   OK             u1   2.73 TB   SATA  -   /c0/e0/slt15 ST3000NC002-1DY166
p24   OK             u0   2.73 TB   SATA  -   /c0/e0/slt16 ST3000NC002-1DY166
p25   VERIFYING      u2   2.73 TB   SATA  -   /c0/e0/slt17 ST33000650NS

```
tw_cli: make controller and unit order consistent

Sort the output by controller ID and Unit ID so that the output ordering is
always consistent. This is necessary to allow tests with multiple controllers
or units to return consistent output.
tw_cli: add test for units/spares during VERIFYING

This test includes 2x RAID-6 units mid-VERIFYING state, and two hot-spare
drives also VERIFYING.
tw_cli: tweak check status for VERIFYING/REBUILDING

VERIFYING is a 'check' state, and REBUILDING is a 'resync' state.
Merge pull request #89 from bootc/tw_cli-verifying-tweaks

tw_cli: tweak VERIFYING state