tar1090-update: don't fail without internet (#250)

instead install the version from the persistent git data if it exists

rootfs/tar1090-install.sh

@@ -69,8 +69,8 @@ function getGIT() {
     rm -rf "$tmp" "$tmp.folder"; popd > /dev/null; return 1;
 }
 
-DB_VERSION_NEW=$(curl --connect-timeout 2 --silent --show-error "https://raw.githubusercontent.com/wiedehopf/tar1090-db/master/version")
-if  [[ "$(cat "$gpath/git-db/version" 2>/dev/null)" != "$DB_VERSION_NEW" ]]; then
+if DB_VERSION_NEW=$(curl --connect-timeout 2 --silent --show-error "https://raw.githubusercontent.com/wiedehopf/tar1090-db/master/version") \
+    && [[ "$(cat "$gpath/git-db/version" 2>/dev/null)" != "$DB_VERSION_NEW" ]]; then
     getGIT "$db_repo" "master" "$gpath/git-db" || true
 fi
 
@@ -95,8 +95,8 @@ if [[ "$1" == "test" ]] || [[ -n "$git_source" ]]; then
     cd "$gpath/git"
     TAR_VERSION="$(cat version)_dirty"
 else
-    VERSION_NEW=$(curl --connect-timeout 2 --silent --show-error "https://raw.githubusercontent.com/wiedehopf/tar1090/master/version")
-    if  [[ "$(cat "$gpath/git/version" 2>/dev/null)" != "$VERSION_NEW" ]]; then
+    if VERSION_NEW=$(curl --connect-timeout 2 --silent --show-error "https://raw.githubusercontent.com/wiedehopf/tar1090/master/version") \
+    && [[ "$(cat "$gpath/git/version" 2>/dev/null)" != "$VERSION_NEW" ]]; then
         if ! getGIT "$repo" "master" "$gpath/git"; then
             echo "Unable to download files, exiting! (Maybe try again?)"
             exit 1