Fix treatment of percent as lvm lv size spec.

Percent is an alternative to a literal size. It is a fixed size request
expressed as a percentage of the vg's free space after all requests with
an explicit size have been allocated (but not grown). That means that a
request defined using percent can still be growable. Such a request will
use the size calculated from the percent argument as the basis for growth
rate.

(cherry picked from commit e0e00f38320bb0b40fb7d8c3e08be2a6fdf5b54e)

Related: rhbz#1116435
Honor zerombr regardless of clearpart setting.

(cherry picked from commit 5b7a54ab78ecf502dc4480200dd784d37b703d19)

Resolves: rhbz#1117946
Honor size specified for explicit extended partition requests.

(cherry picked from commit 24464f98229998742e11446bc05d6adb5b71048e)

Resolves: rhbz#1077250
Remove obsolete conversion of size to float.

(cherry picked from commit d4636acf034a22e20475d7c1ca1e94dc231c7eaf)

Resolves: rhbz#1140642
Try to align end sector up when aligning new partitions.

(cherry picked from commit b7efdc21af277f86fc64b12a1bfcc04623be8748)

Resolves: rhbz#1090477
Align free regions used for partition growing calculations.

Using unaligned free regions only introduces unusable sectors when
calculating growth amounts for aligned partitions.

(cherry picked from commit 79d6f32bbbfd0842f571b4a1903ec76b73afb523)

Resolves: rhbz#1083687