slaprunner: Fix bashism in Nginx & Supervisord logrotate entries

kill -SIGXXX works only in bash and not when the shell is e.g. dash, for
example:

	$ kill -SIGUSR1 1
	/bin/sh: 2: kill: Illegal option -S

This way log rotation for slapproxy.log & friends was not properly working.

Fix it by using `kill -XXX` form which is supported everywhere.

/reviewed-on !402

software/slaprunner/buildout.hash.cfg

@@ -18,7 +18,7 @@ md5sum = 713db528880282d568278f09458d2aab
 
 [template-runner]
 filename = instance-runner.cfg
-md5sum = 04e31ac503753f89510dd412b4680c56
+md5sum = cefbc8abef234c9a74f88688a0ac0030
 
 [template-runner-import-script]
 filename = template/runner-import.sh.jinja2

software/slaprunner/instance-runner.cfg

@@ -354,7 +354,7 @@ context =
 <= logrotate-entry-base
 name = nginx
 log = $${directory:log}/nginx.access.log $${directory:log}/nginx.error.log
-post = kill -SIGUSR1 $(cat $${buildout:directory}/var/run/nginx.pid)
+post = kill -USR1 $(cat $${buildout:directory}/var/run/nginx.pid)
 
 [httpd-parameters]
 path_pid = $${directory:run}/httpd.pid
@@ -797,7 +797,7 @@ wrapper-path = $${directory:services}/supervisord
 <= logrotate-entry-base
 name = supervisord
 log = $${directory:log}/slapproxy.log $${directory:log}/supervisord.log $${directory:log}/supervisord-errors.log
-post = kill -SIGUSR2 $(cat $${buildout:directory}/var/run/supervisord.pid)
+post = kill -USR2 $(cat $${buildout:directory}/var/run/supervisord.pid)
 
 [logrotate-entry-slapgrid]
 <= logrotate-entry-base