Fix missing import of RTSLibBrokenLink
Fix missing import of RTSLibBrokenLink

This patch fixes an import error I introduced in the following commit:

  7f6035f Fix the "unused import" warnings reported by Pylint

Signed-off-by: Christophe Vu-Brugier <1930e27f67e1e10d51770b88cb06d386f1aa46ae@fastmail.fm>

agrover/rtslib-fb,mikenawrocki/rtslib-fb,mikenawrocki/rtslib-fb,cvubrugier/rtslib-fb