mgcp_client: detect SDP section-start parsing errors

After call to mgcp_find_section_end(), actually check the proper variable to
evaluate its return value.

Show in mgcp_client_test output that the parsing errors are fixed, and enable
the assertion that no tests should fail.

Change-Id: I62a2453cd9e2e7d5408423161fa65ec9c9989f98
diff --git a/tests/mgcp_client/mgcp_client_test.err b/tests/mgcp_client/mgcp_client_test.err
index 9079c27..7309242 100644
--- a/tests/mgcp_client/mgcp_client_test.err
+++ b/tests/mgcp_client/mgcp_client_test.err
@@ -15,9 +15,8 @@
 
 test_sdp_section_start() test [0]:
 body: ""
-got rc=0
-FAIL: Expected rc=-22
-got audio_port=0
+DLMGCP MGCP response: cannot find start of SDP parameters
+got rc=-22
 
 test_sdp_section_start() test [1]:
 body: "\n\n"
@@ -51,19 +50,16 @@
 
 test_sdp_section_start() test [7]:
 body: "some mgcp header data\r\nand header params\n\r\nm=audio 23\r\n"
-got rc=0
-FAIL: Expected rc=-22
-got audio_port=0
+DLMGCP MGCP response: cannot find start of SDP parameters
+got rc=-22
 
 test_sdp_section_start() test [8]:
 body: "some mgcp header data\r\nand header params\r\n\rm=audio 23\r\n"
-got rc=0
-FAIL: Expected rc=-22
-got audio_port=0
+DLMGCP MGCP response: cannot find start of SDP parameters
+got rc=-22
 
 test_sdp_section_start() test [9]:
 body: "some mgcp header data\r\nand header params\n\r\rm=audio 23\r\n"
-got rc=0
-FAIL: Expected rc=-22
-got audio_port=0
+DLMGCP MGCP response: cannot find start of SDP parameters
+got rc=-22
 Done