fix(ionView): only $watch attributes if defined
fix(ionView): only $watch attributes if defined

Closes #1216

lutrosis81/manup-app,jango2015/ionic,bankonme/ionic,tkh44/ionic,r14r/fork_ionic_master,100goals/ionic,lutrosis81/manup-app,lewisl9029/ionic,janij/ionic,cbmeeks/ionic,VinceOPS/ionic,deer-hope/ionic,taraszerebecki/ionic,wkrueger/ionic,cnbin/ionic,baiyanghese/ionic,amitparrikar/ionic,jianganglu/ionic,jeremyrussell/ionic,cbmeeks/ionic,microlv/ionic,PressReader/ionic,jgw96/ionic,wkrueger/ionic,thompsonemerson/ionic,x303597316/ionic,lutrosis81/manup-app,envistaInteractive/ionic,Tetpay/ionic,DiZyStudio/ionic,studio666/ionic,baiwyc119/ionic,AmberWhiteSky/ionic,EricCheung3/ionic,uus169/ionic,yalishizhude/ionic,janij/ionic,astagi/ionic,DurgaprasadPati/ionic,n0b0dy897/ionic,eaglesjava/ionic,954053260/ionic,willshen/ionic,lutrosis81/manup-app,r14r-work/fork_ionic,hanmichael/ionic,ahmadawais/ionic,MartinMa/ionic,eaglesjava/ionic,abcd-ca/ionic,oneillsp96/ionic,MarcBT/ionic,zhiqiangli520210/ionic,r14r/fork_ionic_master,angrilove/ionic,hotarzhang/ionic,michaellourenco/ionic,AmberWhiteSky/ionic,qzapaia/ionic,r14r-work/fork_ionic,x303597316/ionic,jomaf1010/ionic,jvkops/ionic,thebigbrain/ionic,abcd-ca/ionic,sthashree/ionic,xzyfer/ionic,MrChen2015/ionic,awhedbee22/ionic,AlphaStaxLLC/ionic,RodrigoIbarraSanchez/ionic,awhedbee22/ionic,edparsons/ionic,janglednerves/ionic,sitacote/ionic-across,janij/ionic,yanzhihong23/ionic-nono,eyalish/ionic,uus169/ionic,urish/ionic,xuyuanxiang/ionic,SaadBinShahid/ionic,cbmeeks/ionic,PressReader/ionic,oneillsp96/ionic,jeremyrussell/ionic,PaperMonster/ionic,guaerguagua/ionic,oabc124/ionic,urish/ionic,LawrenceHan/ionic,Jeremy017/ionic,r14r-work/fork_ionic_master,jvkops/ionic,yurtaev/ionic,TakayukiSakai/ionic,pargatsingh-webklabs/ionic,Baskmart/ionic,chrisbautista/ionic,ctetreault/ionic,chinakids/ionic,chinakids/ionic,JackieLin/ionic,pod4g/ionic,q310550690/ionic,yalishizhude/ionic,Drok1015/ionic,PaperMonster/ionic,Drok1015/ionic,CNVCrew/ionic,openbizgit/ionic,brant-hwang/ionic,janij/ionic,Flllexa/ionic,eyalish/ionic,felquis/ionic,kylezhang/ionic,x303597316/ionic,n0b0dy897/ionic,MartinMa/ionic,zhengqiangzi/ionic,leobetosouza/ionic,leerduo/ionic,thiagofelix/ionic,edwardchor/ionic,ngonzalvez/ionic,uus169/ionic,vjrantal/ionic,leobetosouza/ionic,lazamar/ionic,zhonggaoyong/ionic,NandoKstroNet/ionic,leeric92/ionic,agyrafa/ionic,javascriptit/ionic,buiphu/ionic,timtimUp/ionic,chrisbautista/ionic,xuyuanxiang/ionic,leerduo/ionic,rreinold/FitnessDashboard_IonicApp,ralic/ionic,SobolevLexa/ionic,cnbin/ionic,eyalish/ionic,zyaboutblank/ionic,xzyfer/ionic,AppGyver/ionic,anongtech/ionic,jomaf1010/ionic,sitexa/ionic,zhengqiangzi/ionic,MJefferson/ionic,q310550690/ionic,GeorgeMe/ionic,daew823/ionic,chrisbautista/ionic,felipealbuquerq/ionic,Jeremy017/ionic,MeteorPackaging/ionic,emonidi/ionic,yalishizhude/ionic,fanhaich/ionic,puurinternet/ionic,TakayukiSakai/ionic,emonidi/ionic,jamesdixon/ionic,angrilove/ionic,angrilove/ionic,100goals/ionic,ezc/ionic,jayvi/ionic,eric-stanley/ionic,anongtech/ionic,ralic/ionic,sitexa/ionic,r14r-work/fork_ionic_master,GeorgeMe/ionic,trevorgrayson/ionic,ralic/ionic,thompsonemerson/ionic,baiwyc119/ionic,laispace/ionic,jango2015/ionic,LawrenceHan/ionic,eyalish/ionic,amitparrikar/ionic,zhonggaoyong/ionic,Kryz/ionic,TakayukiSakai/ionic,954053260/ionic,100goals/ionic,oneillsp96/ionic,possan/ionic,ihongcn/ionic,jtomaszewski/ionic,envistaInteractive/ionic,astagi/ionic,vjrantal/ionic,beauby/ionic,q310550690/ionic,felipealbuquerq/ionic,NandoKstroNet/ionic,zittix/ionic,ptarjan/ionic,5amfung/ionic,Sourazou/login,hectoruch/ionic,pargatsingh-webklabs/ionic,yurtaev/ionic,huangsen0912/ionic,shazhumao/ionic,ViniciusAugusto/ionic,leejeap/ionic,Nalinc/ionic,staney7/ionic,r14r-work/fork_ionic,willshen/ionic,vjrantal/ionic,GhostGroup/ionic,Niades/ionic,jianganglu/ionic,jtomaszewski/ionic,rreinold/FitnessDashboard_IonicApp,blueElix/ionic,PaperMonster/ionic,promactkaran/ionic,jamesdixon/ionic,Xeeshan94/ionic,mingming1986/ionic,jayvi/ionic,MartinMa/ionic,5amfung/ionic,WingGao/ionic,femotizo/ionic,ezc/ionic,gyx8899/ionic,hectoruch/ionic,Xeeshan94/ionic,bankonme/ionic,hectoruch/ionic,thiagofelix/ionic,JackieLin/ionic,jgw96/ionic,huangsen0912/ionic,contigo/ionic,xzyfer/ionic,ezc/ionic,fangjing828/ionic,Baskmart/ionic,csbz17027/ionic,DiZyStudio/ionic,KholofeloMoyaba/atajo-ui,Sourazou/login,agyrafa/ionic,guaerguagua/ionic,felquis/ionic,microlv/ionic,sitexa/ionic,leerduo/ionic,bewebltd/ionic,oabc124/ionic,jgw96/ionic,deer-hope/ionic,AndyShiTw/ionic,EricCheung3/ionic,Testoni/ionic,oneillsp96/ionic,fjzdjd/ionic,Baskmart/ionic,brant-hwang/ionic,ptarjan/ionic,xuyuanxiang/ionic,freedomdebug/ionic,5amfung/ionic,janglednerves/ionic,nelsonsozinho/ionic,Gregcop1/ionic,cnbin/ionic,janglednerves/ionic,puurinternet/ionic,freedomdebug/ionic,leeric92/ionic,jayvi/ionic,edwardchor/ionic,MeteorPackaging/ionic,SobolevLexa/ionic,cesarmarinhorj/ionic,amitparrikar/ionic,SaadBinShahid/ionic,leejeap/ionic,NandoKstroNet/ionic,ngonzalvez/ionic,astagi/ionic,ralic/ionic,ddddm/ionic,VinceOPS/ionic,Testoni/ionic,Xeeshan94/ionic,abcd-ca/ionic,daew823/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88/ionic,chrisbautista/ionic,brant-hwang/ionic,studio666/ionic,Gregcop1/ionic,AppGyver/ionic,yanzhihong23/ionic-nono,yanzhihong23/ionic-nono,CNVCrew/ionic,rreinold/FitnessDashboard_IonicApp,jomaf1010/ionic,bewebltd/ionic,leeric92/ionic,thompsonemerson/ionic,xuyuanxiang/ionic,awhedbee22/ionic,nelsonsozinho/ionic,csbz17027/ionic,ihongcn/ionic,angrilove/ionic,yalishizhude/ionic,Drok1015/ionic,taraszerebecki/ionic,rreinold/FitnessDashboard_IonicApp,buiphu/ionic,openbizgit/ionic,zhengqiangzi/ionic,Nalinc/ionic,EricCheung3/ionic,mingming1986/ionic,hotarzhang/ionic,MrChen2015/ionic,openbizgit/ionic,r14r/fork_ionic_master,puurinternet/ionic,treejames/ionic,johnli388/ionic,n0b0dy897/ionic,gyx8899/ionic,ddddm/ionic,amitparrikar/ionic,laispace/ionic,LawrenceHan/ionic,CNVCrew/ionic,vladipus/ionic,MarcBT/ionic,pod4g/ionic,Niades/ionic,fangjing828/ionic,zyaboutblank/ionic,zittix/ionic,GhostGroup/ionic,puurinternet/ionic,kylezhang/ionic,javascriptit/ionic,oabc124/ionic,thebigbrain/ionic,htc550605125/ionic,asfandiyark7/ionic,pargatsingh-webklabs/ionic,Urigo/meteor-ionic,MJefferson/ionic,Flllexa/ionic,AndyShiTw/ionic,guaerguagua/ionic,baiwyc119/ionic,sitacote/ionic-across,MrChen2015/ionic,ddddm/ionic,EricCheung3/ionic,blueElix/ionic,buiphu/ionic,staney7/ionic,youprofit/ionic,promactkaran/ionic,contigo/ionic,leobetosouza/ionic,felipealbuquerq/ionic,ahmadawais/ionic,asfandiyark7/ionic,michaellourenco/ionic,JsonChiu/ionic,celsoyh/ionic,JackieLin/ionic,jvkops/ionic,daew823/ionic,staney7/ionic,leerduo/ionic,janglednerves/ionic,johnli388/ionic,jango2015/ionic,open-anesthesia/ionic,sloops77/ionic,glustful/ionic,blueElix/ionic,johnli388/ionic,jeremyrussell/ionic,gyx8899/ionic,freedomdebug/ionic,MrChen2015/ionic,caiiiycuk/ionic,qzapaia/ionic,954053260/ionic,DurgaprasadPati/ionic,r14r-work/fork_ionic_master