Add the .mvn directory and set default Xmx value
Add the .mvn directory and set default Xmx value

Using the new feature introduced in Maven 3.3.1.
See
https://maven.apache.org/docs/3.3.1/release-notes.html#JVM_and_Command_Line_Options
for more details.

Possibly a long term better solution/first encounter for newcomers. When
people can't build Jenkins because of wrong default memory settings.
Like https://goo.gl/Co9kye

The "Xmx800m" was chosen after looking at last successful ci.j.o builds.
Max memory displayed by Maven being ~730MB. So putting 800 to leave the
build some room so that the GC has less chance to have to chime in too
often.

amuniz/jenkins,varmenise/jenkins,jglick/jenkins,ErikVerheul/jenkins,v1v/jenkins,olivergondza/jenkins,tfennelly/jenkins,ErikVerheul/jenkins,aldaris/jenkins,dennisjlee/jenkins,SebastienGllmt/jenkins,evernat/jenkins,aldaris/jenkins,viqueen/jenkins,daniel-beck/jenkins,tfennelly/jenkins,daniel-beck/jenkins,andresrc/jenkins,gusreiber/jenkins,evernat/jenkins,escoem/jenkins,MichaelPranovich/jenkins_sc,lilyJi/jenkins,bpzhang/jenkins,FarmGeek4Life/jenkins,oleg-nenashev/jenkins,viqueen/jenkins,ndeloof/jenkins,viqueen/jenkins,rlugojr/jenkins,amuniz/jenkins,bkmeneguello/jenkins,dennisjlee/jenkins,evernat/jenkins,dennisjlee/jenkins,samatdav/jenkins,bpzhang/jenkins,samatdav/jenkins,fbelzunc/jenkins,ErikVerheul/jenkins,hplatou/jenkins,dariver/jenkins,pjanouse/jenkins,ydubreuil/jenkins,Ykus/jenkins,vjuranek/jenkins,jglick/jenkins,azweb76/jenkins,ydubreuil/jenkins,rsandell/jenkins,tangkun75/jenkins,SebastienGllmt/jenkins,daniel-beck/jenkins,jpbriend/jenkins,ikedam/jenkins,oleg-nenashev/jenkins,tangkun75/jenkins,amuniz/jenkins,dennisjlee/jenkins,oleg-nenashev/jenkins,Ykus/jenkins,SebastienGllmt/jenkins,MichaelPranovich/jenkins_sc,Jimilian/jenkins,gusreiber/jenkins,ydubreuil/jenkins,MichaelPranovich/jenkins_sc,rsandell/jenkins,sathiya-mit/jenkins,vjuranek/jenkins,rsandell/jenkins,escoem/jenkins,andresrc/jenkins,azweb76/jenkins,Vlatombe/jenkins,fbelzunc/jenkins,pjanouse/jenkins,ErikVerheul/jenkins,tangkun75/jenkins,kohsuke/hudson,kohsuke/hudson,damianszczepanik/jenkins,ErikVerheul/jenkins,MarkEWaite/jenkins,godfath3r/jenkins,ErikVerheul/jenkins,wuwen5/jenkins,daniel-beck/jenkins,recena/jenkins,wuwen5/jenkins,amuniz/jenkins,NehemiahMi/jenkins,Jochen-A-Fuerbacher/jenkins,DanielWeber/jenkins,DanielWeber/jenkins,SebastienGllmt/jenkins,kohsuke/hudson,rsandell/jenkins,jglick/jenkins,gitaccountforprashant/gittest,tfennelly/jenkins,dariver/jenkins,gusreiber/jenkins,NehemiahMi/jenkins,gusreiber/jenkins,wuwen5/jenkins,bkmeneguello/jenkins,protazy/jenkins,christ66/jenkins,rlugojr/jenkins,gitaccountforprashant/gittest,batmat/jenkins,varmenise/jenkins,damianszczepanik/jenkins,MarkEWaite/jenkins,ajshastri/jenkins,recena/jenkins,kohsuke/hudson,sathiya-mit/jenkins,vjuranek/jenkins,rlugojr/jenkins,jenkinsci/jenkins,stephenc/jenkins,jenkinsci/jenkins,ndeloof/jenkins,jpbriend/jenkins,ajshastri/jenkins,aldaris/jenkins,protazy/jenkins,kohsuke/hudson,MarkEWaite/jenkins,escoem/jenkins,varmenise/jenkins,MichaelPranovich/jenkins_sc,wuwen5/jenkins,batmat/jenkins,Jochen-A-Fuerbacher/jenkins,evernat/jenkins,hplatou/jenkins,dennisjlee/jenkins,hplatou/jenkins,lilyJi/jenkins,andresrc/jenkins,recena/jenkins,tfennelly/jenkins,stephenc/jenkins,godfath3r/jenkins,lilyJi/jenkins,Jochen-A-Fuerbacher/jenkins,patbos/jenkins,fbelzunc/jenkins,patbos/jenkins,batmat/jenkins,rlugojr/jenkins,wuwen5/jenkins,gitaccountforprashant/gittest,fbelzunc/jenkins,aldaris/jenkins,samatdav/jenkins,MarkEWaite/jenkins,rlugojr/jenkins,SebastienGllmt/jenkins,hplatou/jenkins,alvarolobato/jenkins,dennisjlee/jenkins,olivergondza/jenkins,bpzhang/jenkins,pjanouse/jenkins,vjuranek/jenkins,bpzhang/jenkins,ydubreuil/jenkins,pjanouse/jenkins,vjuranek/jenkins,hplatou/jenkins,Jimilian/jenkins,viqueen/jenkins,pjanouse/jenkins,godfath3r/jenkins,Jimilian/jenkins,v1v/jenkins,christ66/jenkins,patbos/jenkins,ndeloof/jenkins,NehemiahMi/jenkins,pjanouse/jenkins,escoem/jenkins,gusreiber/jenkins,batmat/jenkins,jglick/jenkins,aldaris/jenkins,stephenc/jenkins,jglick/jenkins,damianszczepanik/jenkins,varmenise/jenkins,dariver/jenkins,stephenc/jenkins,tangkun75/jenkins,ikedam/jenkins,SebastienGllmt/jenkins,fbelzunc/jenkins,olivergondza/jenkins,evernat/jenkins,samatdav/jenkins,DanielWeber/jenkins,alvarolobato/jenkins,tfennelly/jenkins,v1v/jenkins,sathiya-mit/jenkins,pjanouse/jenkins,dariver/jenkins,viqueen/jenkins,Ykus/jenkins,FarmGeek4Life/jenkins,Vlatombe/jenkins,recena/jenkins,MarkEWaite/jenkins,bkmeneguello/jenkins,SebastienGllmt/jenkins,varmenise/jenkins,oleg-nenashev/jenkins,escoem/jenkins,Ykus/jenkins,lilyJi/jenkins,DanielWeber/jenkins,andresrc/jenkins,jpbriend/jenkins,christ66/jenkins,christ66/jenkins,dariver/jenkins,v1v/jenkins,ajshastri/jenkins,bpzhang/jenkins,lilyJi/jenkins,patbos/jenkins,FarmGeek4Life/jenkins,vjuranek/jenkins,stephenc/jenkins,olivergondza/jenkins,Jochen-A-Fuerbacher/jenkins,damianszczepanik/jenkins,v1v/jenkins,FarmGeek4Life/jenkins,protazy/jenkins,NehemiahMi/jenkins,batmat/jenkins,stephenc/jenkins,dariver/jenkins,protazy/jenkins,ikedam/jenkins,NehemiahMi/jenkins,jglick/jenkins,azweb76/jenkins,oleg-nenashev/jenkins,FarmGeek4Life/jenkins,gusreiber/jenkins,Vlatombe/jenkins,andresrc/jenkins,amuniz/jenkins,fbelzunc/jenkins,hplatou/jenkins,alvarolobato/jenkins,Jimilian/jenkins,Jochen-A-Fuerbacher/jenkins,jpbriend/jenkins,ikedam/jenkins,sathiya-mit/jenkins,rlugojr/jenkins,recena/jenkins,recena/jenkins,varmenise/jenkins,damianszczepanik/jenkins,Vlatombe/jenkins,azweb76/jenkins,amuniz/jenkins,DanielWeber/jenkins,sathiya-mit/jenkins,alvarolobato/jenkins,gitaccountforprashant/gittest,Jimilian/jenkins,olivergondza/jenkins,protazy/jenkins,amuniz/jenkins,protazy/jenkins,ajshastri/jenkins,azweb76/jenkins,tangkun75/jenkins,recena/jenkins,aldaris/jenkins,Ykus/jenkins,dariver/jenkins,escoem/jenkins,bkmeneguello/jenkins,ikedam/jenkins,v1v/jenkins,batmat/jenkins,alvarolobato/jenkins,Jochen-A-Fuerbacher/jenkins,rsandell/jenkins,hplatou/jenkins,gusreiber/jenkins,jenkinsci/jenkins,MarkEWaite/jenkins,kohsuke/hudson,damianszczepanik/jenkins,NehemiahMi/jenkins,viqueen/jenkins,jenkinsci/jenkins,jpbriend/jenkins,MarkEWaite/jenkins,ajshastri/jenkins,samatdav/jenkins,samatdav/jenkins,vjuranek/jenkins,ndeloof/jenkins,olivergondza/jenkins,patbos/jenkins,jpbriend/jenkins,tangkun75/jenkins,jglick/jenkins,ydubreuil/jenkins,escoem/jenkins,oleg-nenashev/jenkins,christ66/jenkins,sathiya-mit/jenkins,v1v/jenkins,viqueen/jenkins,ikedam/jenkins,jenkinsci/jenkins,damianszczepanik/jenkins,andresrc/jenkins,ndeloof/jenkins,ikedam/jenkins,lilyJi/jenkins,damianszczepanik/jenkins,Jimilian/jenkins,aldaris/jenkins,dennisjlee/jenkins,Vlatombe/jenkins,FarmGeek4Life/jenkins,stephenc/jenkins,samatdav/jenkins,tangkun75/jenkins,daniel-beck/jenkins,kohsuke/hudson,Ykus/jenkins,varmenise/jenkins,NehemiahMi/jenkins,ErikVerheul/jenkins,DanielWeber/jenkins,Jimilian/jenkins,bpzhang/jenkins,gitaccountforprashant/gittest,jpbriend/jenkins,fbelzunc/jenkins,sathiya-mit/jenkins,rlugojr/jenkins,alvarolobato/jenkins,godfath3r/jenkins,rsandell/jenkins,FarmGeek4Life/jenkins,MichaelPranovich/jenkins_sc,gitaccountforprashant/gittest,evernat/jenkins,godfath3r/jenkins,lilyJi/jenkins,ydubreuil/jenkins,daniel-beck/jenkins,ndeloof/jenkins,jenkinsci/jenkins,andresrc/jenkins,bkmeneguello/jenkins,DanielWeber/jenkins,bpzhang/jenkins,olivergondza/jenkins,Jochen-A-Fuerbacher/jenkins,kohsuke/hudson,jenkinsci/jenkins,ndeloof/jenkins,rsandell/jenkins,rsandell/jenkins,patbos/jenkins,batmat/jenkins,ikedam/jenkins,Vlatombe/jenkins,gitaccountforprashant/gittest,protazy/jenkins,ajshastri/jenkins,MichaelPranovich/jenkins_sc,christ66/jenkins,alvarolobato/jenkins,azweb76/jenkins,patbos/jenkins,ajshastri/jenkins,MichaelPranovich/jenkins_sc,daniel-beck/jenkins,Vlatombe/jenkins,tfennelly/jenkins,tfennelly/jenkins,bkmeneguello/jenkins,Ykus/jenkins,christ66/jenkins,oleg-nenashev/jenkins,MarkEWaite/jenkins,daniel-beck/jenkins,ydubreuil/jenkins,godfath3r/jenkins,azweb76/jenkins,wuwen5/jenkins,jenkinsci/jenkins,wuwen5/jenkins,bkmeneguello/jenkins,godfath3r/jenkins,evernat/jenkins