Fix sed regex from deleting old configs

The regex used to delete old configurations was terminated with a "*",
this caused any bridge configurations to be deleted if they had the same
name in all but the last character.

Also insert a blank line at the end of each config section so the sed
only deletes the section in was intended to delete (it was deleting to
the end of the file)

Fixes-bug: #1327090
Change-Id: I3a62daae94b38976f2b01cd7bc8cd0b4d8e0cd47
Merge "Fix sed regex from deleting old configs"