mr_create: check for empty msg before acting
mr_create: check for empty msg before acting

When creating a merge request in draft mode the message size wasn't being
considered: if it was empty, the code would not check and panic due to a
"slice bounds out of range". This patch basically moves the check for
message existence before the actual manipulation code happens.

Signed-off-by: Bruno Meneguele <82c7731bc2625bcbab88bc571aee6631ba3f66f3@redhat.com>

zaquestion/lab,zaquestion/lab