srsenb.conf.tmpl: reduce RRC inactivity timer to 5s

the default value of 60s is too long to trigger errors in the handling
of this timer. So a 5s timer is more likely to reveal potential issues
during the test execution

Change-Id: Id7a6739487c7875c4f26a47d05978c9ea9f33873

src/osmo_gsm_tester/templates/srsenb.conf.tmpl

@@ -274,7 +274,7 @@ nof_phy_threads  = 1
 #pregenerate_signals  = false
 #tx_amplitude         = 0.6
 #link_failure_nof_err = 50
-#rrc_inactivity_timer = 60000
+rrc_inactivity_timer = 5000
 #max_prach_offset_us  = 30
 #eea_pref_list = EEA0, EEA2, EEA1
 #eia_pref_list = EIA2, EIA1, EIA0