Related-Bug:#1391447
Merged two different flags used for physical topology changes in UI to one
Earlier we were maintaining another flag underlayEnabled in default.config.global.js now we removed this.

Change-Id: I43cf0c05c3f2a31871eab6d540935e66d2aa701c
Merge "Related-Bug:#1391447 Merged two different flags used for physical topology changes in UI to one Earlier we were maintaining another flag underlayEnabled in default.config.global.js now we removed this."