{melodic} libmodbus: set preferred version and unblacklist

* there are 2 versions in meta-oe/thud and another version in melodic:
  meta-ros1-melodic    0.8.8-1 (skipped)
  meta-oe              3.0.6 (skipped)
  meta-oe              3.1.4 (skipped)
* use 0.8 for melodic and 3.1.4 for other ROS distros
* fixes:
ERROR: Nothing RPROVIDES 'libmodbus' (but /jenkins/mjansa/build-ros/ros1-melodic-thud/meta-ros/meta-ros1-melodic/recipes-core/packagegroups/packagegroup-ros-world-melodic.bb, /jenkins/mjansa/build-ros/ros1-melodic-thud/meta-ros/meta-ros1-melodic/generated-recipes/ipr-extern/ipr-extern_0.8.8-1.bb RDEPENDS on or otherwise requires it)
libmodbus was skipped: Recipe is blacklisted: Must specify PREFERRED_VERSION
libmodbus was skipped: Recipe is blacklisted: Must specify PREFERRED_VERSION
libmodbus was skipped: Recipe is blacklisted: Must specify PREFERRED_VERSION
NOTE: Runtime target 'libmodbus' is unbuildable, removing...
Missing or unbuildable dependency chain was: ['libmodbus']
NOTE: Runtime target 'packagegroup-ros-world-melodic' is unbuildable, removing...
Missing or unbuildable dependency chain was: ['packagegroup-ros-world-melodic', 'libmodbus']
NOTE: Runtime target 'packagegroup-ros-world' is unbuildable, removing...
Missing or unbuildable dependency chain was: ['packagegroup-ros-world', 'packagegroup-ros-world-melodic', 'libmodbus']
NOTE: Runtime target 'ros-image-world' is unbuildable, removing...
Missing or unbuildable dependency chain was: ['ros-image-world', 'packagegroup-ros-world', 'packagegroup-ros-world-melodic', 'libmodbus']
NOTE: Runtime target 'ipr-extern' is unbuildable, removing...
Missing or unbuildable dependency chain was: ['ipr-extern', 'libmodbus']
Signed-off-by: Martin Jansa <martin.jansa@lge.com>

meta-ros-common/conf/ros-distro/include/ubuntu-bionic/ros-distro-platform-preferred-versions.inc

@@ -11,5 +11,6 @@ PREFERRED_VERSION_linux-raspberrypi ?= "4.14%"
 # Ubuntu bionic has v4.15, but OpenEmbedded thud only provides v4.14 and v4.18 => select the former to match linux-raspberrypi.
 PREFERRED_VERSION_linux-yocto ?= "4.14%"
 PREFERRED_VERSION_opencv ?= "3.2%"
+PREFERRED_VERSION_libmodbus ?= "3.1.%"
 PREFERRED_VERSION_python-matplotlib ?= "2.1.1"
 PREFERRED_VERSION_yajl ?= "2.1.0"

meta-ros-common/conf/ros-distro/include/ubuntu-bionic/ros-distro-platform-recipe-blacklist.inc

@@ -10,7 +10,6 @@
 # the compilers and runtimes). Remove from the blacklist once a PREFERRED_VERSION_<PN> setting is made in
 # ros-distro-platform-preferred-versions.inc .
 PNBLACKLIST[libgpiod] ?= "Must specify PREFERRED_VERSION"
-PNBLACKLIST[libmodbus] ?= "Must specify PREFERRED_VERSION"
 PNBLACKLIST[linux-yocto-rt] ?= "Must specify PREFERRED_VERSION"
 PNBLACKLIST[linux-yocto-tiny] ?= "Must specify PREFERRED_VERSION"
 PNBLACKLIST[php] ?= "Must specify PREFERRED_VERSION"

meta-ros1-melodic/conf/ros-distro/include/melodic/ros-distro-preferred-versions.inc

@@ -4,3 +4,4 @@
 
 # Set PREFERRED_VERSION_<PN> here for non-platform packages for which the layers provide multiple versions and to override those
 # set in ros-distro-platform-preferred-versions.inc .
+PREFERRED_VERSION_libmodbus = "0.8.%"

meta-ros1-melodic/conf/ros-distro/include/melodic/ros-distro-recipe-blacklist.inc

@@ -6,10 +6,6 @@
 PNBLACKLIST[packagegroup-ros2-demos] ?= "Not a ROS 1 package"
 PNBLACKLIST[packagegroup-ros2-world] ?= "Not a ROS 1 package"
 
-# Initially, blacklist any non-platform duplicates found by "bitbake-layers show-overlayed". Remove from the blacklist once a
-# PREFERRED_VERSION_<PN> setting is made in ros-distro-preferred-versions.inc .
-PNBLACKLIST[libmodbus] ?= "Must specify PREFERRED_VERSION"
-
 # Initially, blacklist any non-platform recipes with multiple versions found by "bitbake-layers show-recipes --multiple". Remove
 # from the blacklist once a PREFERRED_VERSION_<PN> setting is made in ros-distro-preferred-versions.inc .
 # (none)