Re-enabling all disabled items (steps, proposals) if stagemode has changed

- bnc#813072
SLE-11ed the code
Changes file entry
Merge pull request #60 from kobliha/Code-11-SP2

Already approved into master
Do not reset disabled items if there was no previous stagemode
Merge pull request #68 from kobliha/Code-11-SP2

Do not reset disabled items if there was no previous stagemode
New version and changes file entry
Merge pull request #71 from kobliha/Code-11-SP2

New version and changes file entry
Fixed indentation
Exclude InfiniBand from list of devices available on s390. bnc#819327
Updated changelog.
Merge pull request #74 from mchf/Code-11-SP2

Excluded Infiniband device from device types list on s390.
Revert "Do not reset disabled items if there was no previous stagemode"

This reverts commit f6d34af02949ee181bd25162f7603fc35e7896d7.
Revert "SLE-11ed the code"

This reverts commit 2a1541cc48b830dc9b0fa77e428d7e290b835fba.
Revert "Re-enabling all disabled items (steps, proposals) if stagemode has changed"

This reverts commit 17186919b4d977c125212a636863b66d93c99cab.
Added changes file entry - resetting steps
Merge pull request #84 from kobliha/Code-11-SP2

Reverted resetting disabled steps (bnc#813072)
Removed dead code from testsuite.
Modified Netmask::FromBits for longer prefixes.

Do not try handle prefixes longer than 32 bits.
Updated testsuite for Netmask.

Test Netmask::FromBits for prefixes longer than 32bits.