Merge pull request #113 from http-rs/fix-incorrect-comparison

Fix incorrect headervalues comparison

Author: yoshuawuyts

src/headers/header_values.rs

@@ -85,25 +85,25 @@ impl Display for HeaderValues {
 
 impl PartialEq<str> for HeaderValues {
     fn eq(&self, other: &str) -> bool {
-        self.inner[0] == other
+        self.inner.len() == 1 && self.inner[0] == other
     }
 }
 
 impl<'a> PartialEq<&'a str> for HeaderValues {
     fn eq(&self, other: &&'a str) -> bool {
-        &self.inner[0] == other
+        self.inner.len() == 1 && &self.inner[0] == other
     }
 }
 
 impl PartialEq<String> for HeaderValues {
     fn eq(&self, other: &String) -> bool {
-        &self.inner[0] == other
+        self.inner.len() == 1 && &self.inner[0] == other
     }
 }
 
 impl<'a> PartialEq<&String> for HeaderValues {
     fn eq(&self, other: &&String) -> bool {
-        &&self.inner[0] == other
+        self.inner.len() == 1 && &&self.inner[0] == other
     }
 }