arm64: Cleanup previous artifacts before build (#731)

Author: ryonakano

build-pinebookpro.sh

@@ -22,6 +22,7 @@ free_space="500"
 rootdir=$(pwd)
 basedir=$(pwd)/pinebook-pro
 
+rm -rf "${basedir}"
 mkdir -p "${basedir}"
 cd "${basedir}"
 

build-rpi.sh

@@ -24,6 +24,7 @@ version=8.0
 YYYYMMDD="$(date +%Y%m%d)"
 imagename=elementaryos-$version-$channel-rpi-$YYYYMMDD
 
+rm -rf "${basedir}"
 mkdir -p "${basedir}"
 cd "${basedir}"