tests: do not skip installed shell tests

When installed, the test scripts lose their ".sh" suffix, causing them
to be skipped by the "run" script. With this patch, the tests are no
longer specified with ".sh" suffix in the run script, and the suffix
is added automatically as necessary.

LSC: Minor adaptation to keep track of history. As this patch has been
     forward ported into mainline, a simple rebase would loose this
     commit (cf commit 1f317d315c8140c2bcdbff1953a6f645f4f6ef04).

Change-Id: I0b72312e79992b9818559c6546a0e52cd95184c2

test/run

@@ -125,7 +125,7 @@ runtest() {
 		fi
 	else
 		if [ $needroot -eq 1 ]
-		then echo "skipping test$i, not root" >&2 && return 0
+		then echo "skipping test$i, not root." >&2 && return 0
 		else $NAME $ARG || return 1
 		fi
 	fi