Refinesments.

Change-Id: I920eaacb2b4d29fff66ee5fecf2cb8057fbc7f5c

releng/scripts/prebuild.sh

diff --git a/releng/scripts/prebuild.sh b/releng/scripts/prebuild.sh
index 6050a3b..5546020 100644
--- a/releng/scripts/prebuild.sh
+++ b/releng/scripts/prebuild.sh
@@ -19,17 +19,17 @@
 LAST_CLEANED_RECORD="$PRIVATE_MAVEN/.lastCleaned"
 TODAY=`date "+%Y-%m-%d"`
 
+#
+# Function determining whether the private Maven repository should be cleaned.
+#
 need_clean_repo() {
 	if [[ ! -f "$LAST_CLEANED_RECORD" ]]; then
 		return 0; # Initial clean to be recorded
 	fi
 	
-	lcRecord=`cat "$LAST_CLEANED_RECORD"`
 	# The first word of the record is the build ID that was cleaned
-	lastCleanedBuild="${lcRecord%%\ *}"
 	# The rest of the record is the date that it was cleaned
-	lastCleanedDate="${lcRecord#*\ }"
-	
+	read lastCleanedBuild lastCleanedDate < "$LAST_CLEANED_RECORD"
 	
 	# Clean if the last cleaned build was ten builds ago
 	if (( "$BUILD_NUMBER" - "$lastCleanedBuild" >= 10 )); then
@@ -45,6 +45,9 @@
 	return 1
 }
 
+#
+# Function to clean the private maven repository.
+#
 clean_repo() {
 	rm -rf "$PRIVATE_REPO"
 	mkdir -p "$PRIVATE_REPO"