Add fix to ignore valgrind messages related to compressed debug symbols

The glibc package recently enabled compressed debug symbols but valgrind doesn't
support them yet.

Results in messages like:
 --14923-- WARNING: Serious error when reading debug info
 --14923-- When reading debug info from /lib/x86_64-linux-gnu/ld-2.21.so:
 --14923-- Ignoring non-Dwarf2/3/4 block in .debug_info

First line has 'error' in it which triggers some of the ssl-opt tests
diff --git a/tests/ssl-opt.sh b/tests/ssl-opt.sh
index 0d52226..78ca1ca 100755
--- a/tests/ssl-opt.sh
+++ b/tests/ssl-opt.sh
@@ -439,32 +439,33 @@
 
     # check other assertions
     # lines beginning with == are added by valgrind, ignore them
+    # lines with 'Serious error when reading debug info', are valgrind issues as well
     while [ $# -gt 0 ]
     do
         case $1 in
             "-s")
-                if grep -v '^==' $SRV_OUT | grep "$2" >/dev/null; then :; else
+                if grep -v '^==' $SRV_OUT | grep -v 'Serious error when reading debug info' | grep "$2" >/dev/null; then :; else
                     fail "-s $2"
                     return
                 fi
                 ;;
 
             "-c")
-                if grep -v '^==' $CLI_OUT | grep "$2" >/dev/null; then :; else
+                if grep -v '^==' $CLI_OUT | grep -v 'Serious error when reading debug info' | grep "$2" >/dev/null; then :; else
                     fail "-c $2"
                     return
                 fi
                 ;;
 
             "-S")
-                if grep -v '^==' $SRV_OUT | grep "$2" >/dev/null; then
+                if grep -v '^==' $SRV_OUT | grep -v 'Serious error when reading debug info' | grep "$2" >/dev/null; then
                     fail "-S $2"
                     return
                 fi
                 ;;
 
             "-C")
-                if grep -v '^==' $CLI_OUT | grep "$2" >/dev/null; then
+                if grep -v '^==' $CLI_OUT | grep -v 'Serious error when reading debug info' | grep "$2" >/dev/null; then
                     fail "-C $2"
                     return
                 fi