Disable forced sequential tests on Linux

But add a `sleep 1` after starting every test.

The parallel test process will have to be parameterized sometimes in the
future, when more tests are added.

For now, if you don't want to kill your PC with a large number of
parallel tests, I recommend running testAll with seq:
# ./testAll seq

testAll.sh

@@ -13,10 +13,6 @@ if test "$1" = "seq"; then
     sequential=1
 fi
 
-if isOSlinux; then
-    sequential=1
-fi
-
 imunes -i
 
 tests="DHCP DHCP6+RSOL DNS+Mail+WEB OSPF Ping RIP BGP Traceroute services ipsec functional_tests/rj45_vlan"
@@ -37,6 +33,7 @@ for dir in $tests; do
 		sh "test${i}.sh" > TESTRESULTS_$i 2>&1
 	    else
 		sh "test${i}.sh" > TESTRESULTS_$i 2>&1 &
+		sleep 1
 		pids="$pids $!"
 	    fi
 	done
@@ -45,6 +42,7 @@ for dir in $tests; do
 	    sh test.sh > TESTRESULTS 2>&1
 	else
 	    sh test.sh > TESTRESULTS 2>&1 &
+	    sleep 1
 	    pids="$pids $!"
 	fi
     fi