Fix SDK repo to prevent mixing different targets.

This makes sure that sdk-repo-*.zip doesn't exist to
avoid merging into an existing one.

Also fix a warning when generating the repo.xml files.

(cherry picked from commit 4df9f469f7)

Change-Id: Ifeb1234cacf121458bda9d869d7e5df5b5a19673

build/tools/mk_sdk_repo_xml.sh

@@ -267,7 +267,7 @@ function parse_attributes() {
       REV="${BASH_REMATCH[2]}"
     fi
 
-    if [[ $XSD_VERSION -ge $REV ]]; then
+    if [[ ( $REV =~ ^[0-9]+ && $XSD_VERSION -ge $REV ) || $XSD_VERSION == $REV ]]; then
       # Parse the property, if present. Any space is replaced by @
       VALUE=$( grep "^$SRC=" "$PROPS" | cut -d = -f 2 | tr ' ' '@' | tr -d '\r' )
       if [[ -n "$VALUE" ]]; then