fix spelling detected by lintian

Change-Id: I01e54b5cf111677079a8ad57645d3ceb7834702a
diff --git a/src/libmsc/gsm_04_08.c b/src/libmsc/gsm_04_08.c
index 57dff41..ee31747 100644
--- a/src/libmsc/gsm_04_08.c
+++ b/src/libmsc/gsm_04_08.c
@@ -389,7 +389,7 @@
 
 	/* From vlr_loc_update() we expect an implicit dispatch of
 	 * VLR_ULA_E_UPDATE_LA, and thus we expect msc_vlr_subscr_assoc() to
-	 * already have been called and completed. Has an error occured? */
+	 * already have been called and completed. Has an error occurred? */
 
 	vsub = msc_a_vsub(msc_a);
 	if (!vsub) {
@@ -786,7 +786,7 @@
 			 is_utran);
 
 	/* From vlr_proc_acc_req() we expect an implicit dispatch of PR_ARQ_E_START we expect
-	 * msc_vlr_subscr_assoc() to already have been called and completed. Has an error occured? */
+	 * msc_vlr_subscr_assoc() to already have been called and completed. Has an error occurred? */
 	vsub = msc_a_vsub(msc_a);
 	if (!vsub) {
 		LOG_MSC_A(msc_a, LOGL_ERROR, "subscriber not allowed to do a CM Service Request\n");
@@ -1158,7 +1158,7 @@
 			 is_utran);
 
 	/* From vlr_proc_acc_req() we expect an implicit dispatch of PR_ARQ_E_START we expect
-	 * msc_vlr_subscr_assoc() to already have been called and completed. Has an error occured? */
+	 * msc_vlr_subscr_assoc() to already have been called and completed. Has an error occurred? */
 	vsub = msc_a_vsub(msc_a);
 	if (!vsub) {
 		LOG_MSC_A(msc_a, LOGL_ERROR, "subscriber not allowed to do a Paging Response\n");