layer.conf: Use .= for adding to BBPATH and += to BBFILES
layer.conf: Use .= for adding to BBPATH and += to BBFILES

Fixes parsing errors which is appearing after this commit to
meta-openembedded

http://cgit.openembedded.org/meta-openembedded/commit/?id=3c21a46020bd0816579648f684c41dbd6333583e

This triggers
exception NameError: name 'base_contains' is not defined
without this change

Signed-off-by: Andrei Gherzan <0401b4310c02ae595fc6a2b84ead073cab9b0442@windriver.com>

rehsack/meta-openembedded,RedFIR/meta-openembedded,rofehr/meta-openembedded,dongkc/meta-openembedded,openembedded/meta-openembedded,RedFIR/meta-openembedded,fredcadete/meta-openembedded,shr-distribution/meta-oe,MCherifiOSS/meta-openembedded,fredcadete/meta-openembedded,openembedded/meta-openembedded,trikset/meta-openembedded,amery/meta-openembedded,lixinfnst/meta-openembedded,mrchapp/meta-openembedded,RealDigitalMedia/meta-openembedded,amery/meta-openembedded,trikset/meta-openembedded,moto-timo/meta-openembedded,dm8tbr/kodi-wip,akuster/meta-openembedded,RealVNC/yocto_imx6sabreauto_meta-openembedded,trikset/meta-openembedded,openembedded/meta-openembedded,joelagnel/meta-openembedded,dongkc/meta-openembedded,schnitzeltony/meta-openembedded,victronenergy/meta-openembedded,rdm-dev/meta-openembedded,VCTLabs/meta-openembedded,openembedded/meta-openembedded,MCherifiOSS/meta-openembedded,dm8tbr/kodi-wip,rofehr/meta-openembedded,mrchapp/meta-openembedded,VCTLabs/meta-openembedded,VCTLabs/meta-openembedded,rdm-dev/meta-openembedded,joelagnel/meta-openembedded,victronenergy/meta-openembedded,fredcadete/meta-openembedded,shr-distribution/meta-oe,akuster/meta-openembedded,lgirdk/meta-openembedded,akuster/meta-openembedded,RealVNC/yocto_imx6sabreauto_meta-openembedded,shr-distribution/meta-oe,epylar/meta-openembedded,RedFIR/meta-openembedded,rdm-dev/meta-openembedded,rehsack/meta-openembedded,rofehr/meta-openembedded,epylar/meta-openembedded,tobw/meta-openembedded,lgirdk/meta-openembedded,openembedded/meta-openembedded,openembedded/meta-openembedded,RealVNC/yocto_imx6sabreauto_meta-openembedded,rehsack/meta-openembedded,rofehr/meta-openembedded,RealDigitalMedia/meta-openembedded,fredcadete/meta-openembedded,rdm-dev/meta-openembedded,VCTLabs/meta-openembedded,moto-timo/meta-openembedded,rofehr/meta-openembedded,rdm-dev/meta-openembedded,openembedded/meta-openembedded,lixinfnst/meta-openembedded,amery/meta-openembedded,akuster/meta-openembedded,mrchapp/meta-openembedded,tobw/meta-openembedded,RealDigitalMedia/meta-openembedded,martiert/meta-openembedded,amery/meta-openembedded,RealVNC/yocto_imx6sabreauto_meta-openembedded,VCTLabs/meta-openembedded,joelagnel/meta-openembedded,amery/meta-openembedded,victronenergy/meta-openembedded,schnitzeltony/meta-openembedded,martiert/meta-openembedded,epylar/meta-openembedded,rdm-dev/meta-openembedded,shr-distribution/meta-oe,rehsack/meta-openembedded,joelagnel/meta-openembedded,akuster/meta-openembedded,lgirdk/meta-openembedded,trikset/meta-openembedded,rehsack/meta-openembedded,martiert/meta-openembedded,MCherifiOSS/meta-openembedded,dm8tbr/kodi-wip,RealDigitalMedia/meta-openembedded,lixinfnst/meta-openembedded,victronenergy/meta-openembedded,MCherifiOSS/meta-openembedded,rdm-dev/meta-openembedded,epylar/meta-openembedded,fredcadete/meta-openembedded,joelagnel/meta-openembedded,kraj/meta-openembedded,rofehr/meta-openembedded,RedFIR/meta-openembedded,RedFIR/meta-openembedded,schnitzeltony/meta-openembedded,trikset/meta-openembedded,sigma-embedded/elito-org.openembedded.meta,dm8tbr/kodi-wip,shr-distribution/meta-oe,kraj/meta-openembedded,lixinfnst/meta-openembedded,lixinfnst/meta-openembedded,tobw/meta-openembedded,trikset/meta-openembedded,kraj/meta-openembedded,RealDigitalMedia/meta-openembedded,MCherifiOSS/meta-openembedded,RealVNC/yocto_imx6sabreauto_meta-openembedded,tobw/meta-openembedded,lgirdk/meta-openembedded,martiert/meta-openembedded,rofehr/meta-openembedded,rehsack/meta-openembedded,fredcadete/meta-openembedded,VCTLabs/meta-openembedded,joelagnel/meta-openembedded,dongkc/meta-openembedded,schnitzeltony/meta-openembedded,RedFIR/meta-openembedded,shr-distribution/meta-oe,fredcadete/meta-openembedded,sigma-embedded/elito-org.openembedded.meta,trikset/meta-openembedded,RedFIR/meta-openembedded,rehsack/meta-openembedded,moto-timo/meta-openembedded,rofehr/meta-openembedded,dm8tbr/kodi-wip,epylar/meta-openembedded,amery/meta-openembedded,VCTLabs/meta-openembedded,kraj/meta-openembedded,victronenergy/meta-openembedded,dm8tbr/kodi-wip,martiert/meta-openembedded,amery/meta-openembedded,moto-timo/meta-openembedded,epylar/meta-openembedded,dongkc/meta-openembedded,openembedded/meta-openembedded,sigma-embedded/elito-org.openembedded.meta,sigma-embedded/elito-org.openembedded.meta,victronenergy/meta-openembedded,sigma-embedded/elito-org.openembedded.meta,mrchapp/meta-openembedded,lgirdk/meta-openembedded,joelagnel/meta-openembedded,schnitzeltony/meta-openembedded,sigma-embedded/elito-org.openembedded.meta,dongkc/meta-openembedded,shr-distribution/meta-oe,kraj/meta-openembedded,epylar/meta-openembedded,schnitzeltony/meta-openembedded,trikset/meta-openembedded,tobw/meta-openembedded,moto-timo/meta-openembedded,dm8tbr/kodi-wip,dm8tbr/kodi-wip,epylar/meta-openembedded,lixinfnst/meta-openembedded,sigma-embedded/elito-org.openembedded.meta,fredcadete/meta-openembedded,kraj/meta-openembedded,MCherifiOSS/meta-openembedded,victronenergy/meta-openembedded,mrchapp/meta-openembedded,shr-distribution/meta-oe,joelagnel/meta-openembedded,RedFIR/meta-openembedded,rdm-dev/meta-openembedded,kraj/meta-openembedded,tobw/meta-openembedded,mrchapp/meta-openembedded,VCTLabs/meta-openembedded,lgirdk/meta-openembedded,mrchapp/meta-openembedded,schnitzeltony/meta-openembedded,amery/meta-openembedded,lgirdk/meta-openembedded