Make env in plasma-sourceenv.sh call portable

Summary: This failed for me on FreeBSD where env doesn't support -0. Fall back to genv which does.

Reviewers: fvogt, adridg, apol

Reviewed By: fvogt, apol

Subscribers: plasma-devel

Tags: #plasma

Differential Revision: https://phabricator.kde.org/D25124

startkde/plasma-sourceenv.sh

@@ -3,4 +3,5 @@ do
     . $i >/dev/null
 done
 
-env -0
+# env may not support -0, fall back to GNU env
+env -0 2>/dev/null || genv -0