fdisk: fix copy from readline and whitespace stripping

fdisk: fix copy from readline and whitespace stripping

Bug fixed:
---
678: fdisk:      ASK: asking for number ['Partition number', <1,4>, default=1, range: 1-4]
678: fdisk:      ASK: asking for user replay [interactive]
Partition number (1-4, default 1): 12345
678: fdisk:      ASK: user's reply: >>>12345<<<
Value out of range.
678: fdisk:      ASK: asking for user replay [interactive]
Partition number (1-4, default 1): 1
678: fdisk:      ASK: user's reply: >>>12345<<<
Value out of range.
678: fdisk:      ASK: asking for user replay [interactive]
Partition number (1-4, default 1):
678: fdisk:      ASK: user's reply: >>>22345<<<
Value out of range.
---

Signed-off-by: Vaclav Dolezal <vdolezal@redhat.com>