Fix quotes around gcovr install command

Author: Jenny Plunkett

UNITTESTS/README.md

@@ -45,7 +45,7 @@ sudo easy_install pip
 
 ### Installing covr
 
-Install gcovr code coverage tool globally with `pip install 'gcovr>=4.1'` or using virtualenv:
+Install gcovr code coverage tool globally with `pip install "gcovr>=4.1"` or using virtualenv:
 
 #### virtualenv
 
@@ -291,4 +291,4 @@ TEST_F(TestSemaphore, constructor)
 
 **Problem:** virus protection identifies files generated by CMake as malicious and quarantines the files on Windows.
 
-* **Solution**: restore the false positive files from the quarantine.
+* **Solution**: restore the false positive files from the quarantine.