tizen: Bump to 1.2.0+RC1

tizen: Bump to 1.2.0+RC1

In master branch closest tag is currently 1.2.0-RC1,
but can't be used as RPM does not allow to use "-" in version,
so it needs to be aliased:
make sure to create a tag before using gbsbuild
  git tag 1.2.0+RC1 1.2.0-RC1

Bug-Tizen: https://bugs.tizen.org/jira/browse/TINF-861
Change-Id: Ia58a4f66793506c80f5e7bc5da6e895deb79e288
Origin: https://gerrit.iotivity.org/gerrit/#/c/13515/
Signed-off-by: Philippe Coval <philippe.coval@osg.samsung.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/13515
Tested-by: jenkins-iotivity <jenkins@iotivity.org>
Reviewed-by: Ziran Sun <ziran.sun@samsung.com>