`nimble remove` skips some packages
I'm not sure what it's based on, but `nimble remove` sometimes skips one of the packages it's given:
```
[dmitry@dmitry nimfoo]$ nimble install -y nimfp@0.4.2 nimboost@0.5.4
Downloading https://github.com/vegansk/nimfp using git
   Warning: Package 'nimfp' has an incorrect structure. The top level of the package source directory should contain at most one module, named 'nimfp.nim', but a file named 'fp.nim' was found. This will be an error in the future.
      Hint: If this is the primary source file in the package, rename it to 'nimfp.nim'. If it's a source file required by the main module, or if it is one of several modules exposed by 'nimfp', then move it into a 'nimfp/' subdirectory. If it's a test file or otherwise not required to build the the package 'nimfp.nim', prevent its installation by adding `skipFiles = @["fp.nim"]` to the .nimble file. See https://github.com/nim-lang/nimble#libraries for more info.
  Verifying dependencies for nimfp@0.4.2
 Installing nimboost@>= 0.5.3
Downloading https://github.com/vegansk/nimboost using git
   Warning: Package 'nimboost' has an incorrect structure. It should contain a single directory hierarchy for source files, named 'nimboost', but file 'richstring.nim' is in a directory named 'boost' instead. This will be an error in the future.
      Hint: If 'boost' contains source files for building 'nimboost', rename it to 'nimboost'. Otherwise, prevent its installation by adding `skipDirs = @["boost"]` to the .nimble file.
  Verifying dependencies for nimboost@0.5.4
      Info: Dependency on patty@>= 0.3.1 already satisfied
  Verifying dependencies for patty@0.3.1
 Installing nimboost@0.5.4
   Success: nimboost installed successfully.
      Info: Dependency on classy@>= 0.0.2 already satisfied
  Verifying dependencies for classy@0.0.2
 Installing nimfp@0.4.2
   Success: nimfp installed successfully.
Downloading https://github.com/vegansk/nimboost using git
  Verifying dependencies for nimboost@0.5.4
      Info: Dependency on patty@>= 0.3.1 already satisfied
  Verifying dependencies for patty@0.3.1
 Installing nimboost@0.5.4
    Prompt: nimboost@0.5.4 already exists. Overwrite? -> [forced yes]
   Success: nimboost installed successfully.
[dmitry@dmitry nimfoo]$ nimble remove -y nimfp nimboost
    Looking for nimfp (any version)
   Checking reverse dependencies
    Looking for nimboost (any version)
   Checking reverse dependencies
    Prompt: The following packages will be removed:
        ...   nimfp (0.4.2)
        ... Do you wish to continue? -> [forced yes]
    Removed nimfp (0.4.2)
```
note that `nimboost`'s reverse dependencies are checked, but it is not removed.

My guess is that this probably based on dependencies (`nimfp` depends on `nimboost`), but in any case `nimble remove` shouldn't silently skip the specified package.