CI/travis/lib.sh: rework artifact removal via SFTP

We can avoid downloading artifacts to check if they exist, by trying to
remove them. If this operation errors out, it's fine, and we can move ahead
with uploading the artifacts (as before).
This saves a bit of time and some bandwidth.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>

CI/travis/lib.sh

@@ -163,6 +163,35 @@ brew_install_or_upgrade() {
 	done
 }
 
+sftp_cmd_pipe() {
+	sftp ${EXTRA_SSH} ${SSHUSER}@${SSHHOST}
+}
+
+sftp_rm_artifact() {
+	local artifact="$1"
+	sftp_cmd_pipe <<-EOF
+		cd ${DEPLOY_TO}
+		rm ${artifact}
+	EOF
+}
+
+sftp_upload() {
+	local FROM="$1"
+	local TO="$2"
+	local LATE="$3"
+
+	sftp_cmd_pipe <<-EOF
+		cd ${DEPLOY_TO}
+
+		put ${FROM} ${TO}
+		ls -l ${TO}
+
+		symlink ${TO} ${LATE}
+		ls -l ${LATE}
+		bye
+	EOF
+}
+
 upload_file_to_swdownloads() {
 
 	if [ "$#" -ne 4 ] ; then
@@ -200,27 +229,15 @@ upload_file_to_swdownloads() {
 	echo and ${branch}_${LIBNAME}${LDIST}${EXT}
 	ssh -V
 
-	if curl -m 10 -s -I -f -o /dev/null http://swdownloads.analog.com/cse/travis_builds/${TO} ; then
-		local RM_TO="rm ${TO}"
-	fi
-
-	if curl -m 10 -s -I -f -o /dev/null http://swdownloads.analog.com/cse/travis_builds/${LATE} ; then
-		local RM_LATE="rm ${LATE}"
-	fi
-
-	sftp ${EXTRA_SSH} ${SSHUSER}@${SSHHOST} <<-EOF
-		cd ${DEPLOY_TO}
-
-		${RM_TO}
-		put ${FROM} ${TO}
-		ls -l ${TO}
+	for rmf in ${TO} ${LATE} ; do
+		sftp_rm_artifact ${rmf} || \
+			echo_blue "Could not delete ${rmf}"
+	done
 
-		${RM_LATE}
-		symlink ${TO} ${LATE}
-		ls -l ${LATE}
-		bye
-	EOF
-	[ "$?" = "0" ] || return 1
+	sftp_upload "${FROM}" "${TO}" "${LATE}" || {
+		echo_red "Failed to upload artifact from '${FROM}', to '${TO}', symlink '${LATE}'"
+		return 1
+	}
 
 	# limit things to a few files, so things don't grow forever
 	if [ "${EXT}" = ".deb" ] ; then