Fix small leak when parsing ‘--ignore-depends’ option values

debian/changelog

@@ -8,6 +8,7 @@ dpkg (1.15.5) UNRELEASED; urgency=low
   * Check and warn on duplicate conffiles in dpkg-deb. Closes: #131633
   * Make the upstream build system silent by default with automake 1.11 or
     newer, and always verbose when building the Debian packages.
+  * Fix small leak when parsing ‘--ignore-depends’ option values.
 
   [ Raphaël Hertzog ]
   * Add versioned dependency on base-files (>= 5.0.0) to dpkg-dev to ensure

src/main.c

@@ -287,6 +287,8 @@ static void ignoredepends(const struct cmdinfo *cip, const char *value) {
 
     p+= strlen(p)+1;
   }
+
+  free(copy);
 }
 
 static void setinteger(const struct cmdinfo *cip, const char *value) {