tests: update README.md with a missing single quote

Closes #7231

diff --git a/tests/README.md b/tests/README.md
index 809ca2f36d0bdb908d8dc6e878c9d53f41087ac6..3ecfb4ac07db02b0efbc03e5a973828d0460d7f7 100644 (file)
--- a/tests/README.md
+++ b/tests/README.md
@@ -161,7 +161,7 @@
 
   gcc provides a tool that can determine the code coverage figures for the
   test suite.  To use it, configure curl with `CFLAGS='-fprofile-arcs
-  -ftest-coverage -g -O0`.  Make sure you run the normal and torture tests to
+  -ftest-coverage -g -O0'`.  Make sure you run the normal and torture tests to
   get more full coverage, i.e. do:
 
     make test