Update the cleanspec to clean libwebcore.
Update the cleanspec to clean libwebcore.

Change-Id: Ie27e0e1c8a617199f1d8ff0b484936ccd14b04de

ND-3500/platform_manifest,xorware/android_build,xorware/android_build,fallouttester/platform_manifest,xorware/android_build,xorware/android_build,see4ri/lolili,pranav01/platform_manifest,knone1/platform_manifest,xorware/android_build,RR-msm7x30/platform_manifest,hagar006/platform_manifest,Hybrid-Power/startsync