Make code for running lvm and reporting error (if any) reusable
Make code for running lvm and reporting error (if any) reusable

This will be useful for a lot of lvm functions in the future.

atodorov/libblockdev,rhinstaller/libblockdev,dashea/libblockdev,snbueno/libblockdev,atodorov/libblockdev,vpodzime/libblockdev,rhinstaller/libblockdev,dashea/libblockdev,vpodzime/libblockdev,snbueno/libblockdev,rhinstaller/libblockdev,vpodzime/libblockdev,atodorov/libblockdev