Use smarter method of determining kernel version

Try to use:
1. Version set up in environment (KVERS variable)
2. running kernel's version if headers are available
3. newest-built of installed kernel-devel's versions

Change-Id: If59c2e572a91998483da4eca78c091990cb045fc
Partial-Bug: 1759561

Makefile

@@ -9,8 +9,8 @@ DEPENDENCIES 	:= $(patsubst %.spec,dep-%,$(notdir $(SPEC_FILES)))
 DEBUGINFO    ?= TRUE
 TOPDIR       ?= $(SB_TOP)
 SCONSOPT     ?= production
-SRCVER       ?= $(shell cat $(SB_TOP)/controller/src/base/version.info)
-KVERS        ?= $(shell rpm -q --qf "%{VERSION}-%{RELEASE}.%{ARCH}" kernel-devel)
+SRCVER       ?= $(shell cat $(SB_TOP)controller/src/base/version.info)
+KVERS        ?= $(shell $(MKFILE_DIR)utils/get_kvers.sh)
 BUILDTAG     ?= $(shell date +%m%d%Y%H%M)
 SKUTAG       ?= ocata
 MANIFESTFILE ?= $(SB_TOP).repo/manifest.xml

utils/get_kvers.sh

@@ -0,0 +1,13 @@
+#!/bin/bash
+
+running_kver=$(uname -r) 
+if [[ -d "/lib/modules/${running_kver}/build" ]]; then
+  # Running kernel's sources are available
+  kvers=${running_kver}
+else
+  # Let's use newest installed version of kernel-devel
+  kvers=$(rpm -q kernel-devel --queryformat="%{buildtime}\t%{VERSION}-%{RELEASE}.%{ARCH}\n" | sort -nr | head -1 | cut -f2)
+fi
+
+echo ${kvers}
+