Fix race when testing for ETXTBSY writing to ${n0} (process image) by making

sure the process has been started beforehand with pgrep

pkill the process afterwards to make sure it's dead when the unlink is run
(not strictly required, but I was being conservative)

MFC after: 1 week
Reviewed by: Darius O'Conner, mjohnston
Sponsored by: EMC / Isilon Storage Division

contrib/pjdfstest/tests/open/20.t

@@ -14,7 +14,11 @@ n0=`namegen`
 
 cp -pf `which sleep` ${n0}
 ./${n0} 3 &
+while ! pkill -0 -f ./${n0}; do
+	sleep 0.1
+done
 expect ETXTBSY open ${n0} O_WRONLY
 expect ETXTBSY open ${n0} O_RDWR
 expect ETXTBSY open ${n0} O_RDONLY,O_TRUNC
+pkill -9 -f ./${n0}
 expect 0 unlink ${n0}

contrib/pjdfstest/tests/truncate/11.t

@@ -14,5 +14,9 @@ n0=`namegen`
 
 cp -pf `which sleep` ${n0}
 ./${n0} 3 &
+while ! pkill -0 -f ./${n0}; do
+	sleep 0.1
+done
 expect ETXTBSY truncate ${n0} 123
+pkill -9 -f ./${n0}
 expect 0 unlink ${n0}