libcap: rename existing patch

libcap currently has one patch, but it is named using the old naming
strategy, which includes the package version, but not a patch
number. This commit switches this to use the new patch naming
strategy.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Acked-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Acked-by: Samuel Martin <s.martin49@gmail.com>