MT#55283 615_kernel-modules: check for exact match of rtpengine kernel module

With the renamed rtpengine kernel module (from xt_RTPENGINE into
nft_rtpengine), we have three instead of only two matches in the lsmod
output:

  [sipwise-lab-trunk] root@sp1:~# lsmod | grep nft_rtpengine
  nft_rtpengine          94208  4
  nf_tables             380928  13 nft_rtpengine
  x_tables               53248  2 nft_rtpengine,ip_tables

Let's check for the exact module name only, since we don't need to check
its dependencies.

Fixes:

| not ok 22 - Command: lsmod | grep -Ec "xt_RTPENGINE|nft_rtpengine": stdout: Expected "object: *bytes.Reader" to have patterns ["/^2$/"] the missing elements were ["/^2$/"]

Change-Id: I5e3be48ac43d82321a31fd2c2f8ae9ce3ce2f598

templates/615_kernel-modules.yaml.tt2

@@ -12,9 +12,9 @@ command:
     stderr: []
 {{if and [% (rtpengine.enable == "yes" && is_proxy) ? 1 : 0 %] .Vars.NODE_ACTIVE}}
 
-  lsmod | grep -Ec "xt_RTPENGINE|nft_rtpengine":
+  lsmod | grep -Ec "^(xt_RTPENGINE|nft_rtpengine)":
     exit-status: 0
     stdout:
-      - '/^2$/'
+      - '/^1$/'
     stderr: []
 {{end}}