buildroot

package/git: bump version to 2.15.0

To avoid the build error

grep.c:(.text+0xa02): undefined reference to `pcre_jit_exec'

we need to add NO_LIBPCRE1_JIT=1 according to
https://www.spinics.net/lists/git/msg314515.html

Signed-off-by: Bernd Kuhls <bernd.kuhls@t-online.de>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>