Changes

contrib/jenkins.sh: clean up embedded build flags

--enable-embedded implies the following flags:

* --disable-log-macros
* --disable-libsctp
* --disable-libusb
* --disable-gb
* --disable-libmnl
* --disable-syslog-logging

so they can be safely removed.

--enable-external-tests makes no sense for an embedded build.

Change-Id: I4b54ecc5b023c7f4e1788814960e179c3818dbda
Related: libosmocore.git I164eb461fb59c7675393219102740f40c1119fdd