hooks/pre-auto-gc: fix AC detection on OSX Maverick
hooks/pre-auto-gc: fix AC detection on OSX Maverick

The output of pmset has been changed to "Now drawing from 'AC Power'"

Change-Id: Id425d3bcd6a28656736a6d2c3096623a3ec053cc

wzhy90/git-repo,opencontrail-ci-admin/git-repo,petemoore/git-repo,petemoore/git-repo,qioixiy/git-repo,eligoenergy/git-repo,xecle/git-repo,flingone/git-repo,jcfrank/myrepo,jcfrank/myrepo,jingyu/git-repo,ChronoMonochrome/repo,windyan/git-repo,GerritCodeReview/git-repo,eligoenergy/git-repo,dodocat/git-repo,slfyusufu/repo,codetutil/git-repo,ronan22/repo,lchiocca/repo,wavecomp/git-repo,opensourcechipspark/repo,gbraad/git-repo,chenzilin/git-repo,TheQtCompany/git-repo,lipro-yocto/git-repo,FuangCao/git-repo,11NJ/git-repo,mixedpuppy/git-repo,flingone/git-repo,demonyangyue/git-repo,eric011/git-repo,opencontrail-ci-admin/git-repo,hisilicon/git-repo,zemug/repo,kdavis-mozilla/repo-repo,loungin/git-repo,slfyusufu/repo,xianyo/git-repo,dodocat/git-repo,lchiocca/repo,loungin/git-repo,RuanJG/git-repo,hacker-camp/google_repo,4455jkjh/repo,RuanJG/git-repo,venus-solar/git-repo,daimajia/git-repo,testbetta/repo-pub,kangear/git-repo,eric011/git-repo,demonyangyue/git-repo,FuangCao/git-repo,FuangCao/repo,mer-tools/git-repo,ChronoMonochrome/repo,jingyu/git-repo,nuclearmistake/repo,4455jkjh/repo,TheQtCompany/git-repo,DavidPu/git-repo,DavidPu/git-repo,xin3liang/git-repo,windyan/git-repo,darrengarvey/git-repo,kdavis-mozilla/repo-repo,GatorQue/git-repo-flow,biaolv/git-repo,derron/git-repo,lshain/repo,linuxdeepin/git-repo,codetutil/git-repo,frogbywyplay/git-repo,testbetta/git-repo-pub,ilansmith/repo,darrengarvey/git-repo,ceejatec/git-repo,chenzilin/git-repo,GerritCodeReview/git-repo,simbasailor/git-repo,zemug/repo,CyanogenMod/tools_repo,mixedpuppy/git-repo,duralog/repo,GatorQue/git-repo-flow,aosp-mirror/tools_repo,Pivosgroup/google-git-repo,nuclearmistake/repo,biaolv/git-repo,lewixliu/git-repo,simbasailor/git-repo,lshain/repo,gabbayo/git-repo,chzhong/git-repo,lipro-yocto/git-repo,11NJ/git-repo,FuangCao/repo,lewixliu/git-repo,couchbasedeps/git-repo,xianyo/git-repo,testbetta/repo-pub,kangear/git-repo,wzhy90/git-repo,hacker-camp/google_repo,FlymeOS/repo,llg84/google_repo,lightsofapollo/git-repo,xin3liang/git-repo,ronan22/repo,venus-solar/git-repo,wavecomp/git-repo,xyyangkun/git-repo,ediTLJ/git-repo,qioixiy/git-repo,chzhong/git-repo,linuxdeepin/git-repo,IbpTeam/repo,duralog/repo,lightsofapollo/git-repo,testbetta/git-repo-pub,FlymeOS/repo,iAlios/git-repo,frogbywyplay/git-repo,xyyangkun/git-repo,ilansmith/repo,ediTLJ/git-repo,IbpTeam/repo,ceejatec/git-repo,qupai/git-repo,llg84/google_repo,opensourcechipspark/repo,aosp-mirror/tools_repo,Pivosgroup/google-git-repo,xecle/git-repo,hisilicon/git-repo,daimajia/git-repo,gbraad/git-repo,gabbayo/git-repo,mer-tools/git-repo,CyanogenMod/tools_repo,mozilla/git-repo,iAlios/git-repo,couchbasedeps/git-repo,mozilla/git-repo,derron/git-repo,qupai/git-repo