Fixes env in runtest

When the parameter of 'env' is parsed the first time, it adds an extra
space in the front. When the script kicks off each test, this extra
space is not a correct form the script want to interpret and it
complains in the output: "not in a=b form".
Signed-off-by: Wesley Bland <wbland@anl.gov>

test/mpi/runtests.in

@@ -439,7 +439,12 @@ sub RunList {
 		    $mpiexecArgs = "$mpiexecArgs $value";
 		}
 		elsif ($key eq "env") {
-		    $progEnv = "$progEnv $value";
+		    if ($progEnv eq "") {
+			$progEnv = "$value";
+		    }
+		    else {
+			$progEnv = "$progEnv $value";
+		    }
 		}
 		elsif ($key eq "mpiversion") {
 		    $mpiVersion = $value;