travisify.sh: use xmllint to extract repoSlug

We already require xmllint for the other POM extractions. It is more
robust in that it will always find the correct child element, whereas
grep alone might conceivably pick up anything such as an XML comment.

Author: ctrueden

travisify.sh

@@ -66,7 +66,7 @@ process() {
 	cd "$1"
 
 	# -- Git sanity checks --
-	repoSlug=$(grep '<connection>' pom.xml 2>/dev/null | sed 's/[^>]*>//' | sed 's/<.*//' | cut -d'/' -f4,5)
+	repoSlug=$(xmllint --xpath "//*[local-name()='project']/*[local-name()='scm']/*[local-name()='connection']" pom.xml|sed 's_.*github.com[:/]\(.*\)<.*_\1_')
 	test "$repoSlug" && info "Repository = $repoSlug" || die 'Could not determine GitHub repository slug'
 	git fetch >/dev/null
 	git diff-index --quiet HEAD -- || die "Dirty working copy"