Fixed package_yum to work on CentOS

conf/explorer/os

@@ -49,6 +49,12 @@ if grep -q ^Fedora /etc/redhat-release 2>/dev/null; then
    exit 0
 fi
 
+# CentOS is also based on Redhat, this return before redhat!
+if grep -q ^CentOS /etc/redhat-release 2>/dev/null; then
+    echo centos
+    exit 0
+fi
+
 if [ -f /etc/redhat-release ]; then
    echo redhat
    exit 0

conf/explorer/os_version

@@ -39,7 +39,7 @@ case "$($__explorer/os)" in
    macosx|*bsd|solaris)
       uname -r
    ;;
-   redhat)
+   redhat|centos)
       cat /etc/redhat-release
    ;;
    suse)