Travis OSX images don't contain oclint anymore

This was a common issue in Travis builds across many projects, so the
people at Travis decided to uninstall oclint by default. Details in
https://changelog.travis-ci.com/oclint-is-removed-from-mac-builds-79270

Signed-off-by: Rodrigo Tobar <rtobar@icrar.org>

.travis/before_install.sh

@@ -42,13 +42,6 @@ then
 		brew update || fail "cannot update brew"
 	fi
 
-	# The xcode 8.1 and 9.1 images need oclint to be uninstalled
-	# (see travis-ci issue #8826)
-	if [ "${XCODE}" = "8.1" -o "${XCODE}" = "9.1" ]
-	then
-		brew cask uninstall oclint || fail "cannot uninstall oclint"
-	fi
-
 	# cxxtest pulls python@2, so we need to unlink
 	# the pre-installed python first
 	brew unlink python || fail "cannot unlink python"